Look, I'm going to start this off by agreeing with you that the author has improperly associated all of Islam with these kinds of hatred and bigotries and it is a very peculiar article to be posted to this website.

The next part here gets tricky. Firstly, all Islam is not the same, but far-right fundamentalist Islam is pretty the same across the board and is hard to distinguish whether or not it's in the minority or the majority.

Given that the majority of the world's Muslims live in Southeast Asia, it's hard to distinguish Islam's cultural lean worldwide. So it makes much more sense to limit the issue to the kind of Islam our original poster is discussing (and indeed the kind most are discussing when breaching this issue), which is clearly Middle Eastern fundamentalist Islam.

Fundamentalist Islam is dangerous, just as the other fundamentalist Abrahamic faiths are of course. After all, according to the FBI there were more domestic terror attacks over the last decade in the United States separately by extremist Latin, Jewish and White terror groups than there were from all combined Muslim groups. The dangers from such extremism should be, and generally are, taken seriously in every Western nation.

Now, the encroaching push of Islamic values into Western society is largely a bogeyman. Speaking from a purely statistical standpoint, the West is becoming more and more secular and Islam isn't really doing anything to change that fact.

The general scare tactic used by Islamaphobes is the "birth-rate" of Muslims would increase therefore increasing the Muslim population in Europe (a non-issue for America). However, the Pew Research Center conducted a study that found the Muslim birth-rate is actually decreasing in Europe and will drop from the current 2.2 to 2.0 by 2030, while the non-Muslim population is expected to increase from 1.5 to 1.6 in that same time-frame. When you factor in the secularization that naturally occurs in Europe's religious population, then you're looking at the very most, a 1-1.5% increase in the practicing Muslim population in Europe by 2030, with an even smaller portion than that (less than 30%) holding onto the culture maladies of fundamentalism.

Now, long-term we can establish that it is very unlikely that Islam will have much, if any, impact on Europe in the long-run. There will be no "Islamification" of Europe (and especially not America since the numbers stateside are significantly lower than that of Europe combined with a significantly lower tolerance level for Islamic fundamentalism culturally and politically).

With that being said, this does not discount the threat a vocal minority to pose to any larger population that refuses to address its discriminatory practices. I don't take this young man's anecdotes as any form of evidence beyond what they are, anecdotal. But it bears asking the question of the place religious fundamentalism deserves to hold in the public square. Should their beliefs be met with xenophobia and bigotry? Of course not. But every European and American citizen is well within their rights to question the validity of both their beliefs and the methods by which fundamentalists wish to impose said beliefs.

To your point about defamation and rumor spreading being a "sin" in Islam. There is an insidious justification that fundamentalists use when engaging in defamation and backbiting. The Quran specifically states that if a person is guilty of the actions for which they are being defamed and slandered over, then it is not a sin in the eyes of God. Now, there is supposed to be a precondition under which the person spreading the rumor is supposed to do so only to clarify what is true and/or false, but in the eyes of these fundamentalists they've already judged the victim party guilty. This judgement is then verified in their gossipy clique of other fundamentalists. It's an Ouroboros of hatred and judgement that sadly is thrust mostly on women.

Now, this isn't a problem with "Islam" per se, but rather a problem with fundamentalism and specifically Middle Eastern cultural fundamentalism. The groups discussed in this young man's article certainly exist in Europe. It should be fairly obvious that outside of one corner of this one University there is little to no effective power these groups have as they're enjoying the protection afforded by a University clearly desperate to avoid controversy.

Of course, because of the original author's unwillingness to identify his University, there isn't much in the way of affirming any of this, so the best we can do is address the groups that do in fact exist. The best way to deal with such groups is to meet them with a firm secular humanist stand that encourages assimilation with the cultural norms of the country while respecting their freedom of religion (which stops the second it seeks to limit the freedom of others in America and most of Europe).

Those groups that do exist can pose a real threat, but it is unlikely they pose any more threat than any other extremist group. There are always the nuts and the disadvantaged being used and using others to accomplish the bizarre machinations of a deluded hive mind. But this isn't when fear should be entertained, but rather courage and an enduring passion for the dignity and improvement of all humanity.

At least, those are the lofty ideals I think the majority of us cosmopolitan youths wish to aspire toward. It's just important to remember that confirmation bias in situations of race and religion tend to get manifest quickly and on a subconscious level. Doing our best to mitigate how we let those biases affect our rational minds is probably the best we can wish for on a mass scale.