> I mean that he has very little evidence for his claims

This is not just his claims. This is pretty self-evident to those who are on the other side of the political spectrum which admittedly most IT/software crowd are not.

https://thecritic.co.uk/the-left-wing-bias-of-wikipedia/

"A 2018 study by Shane Greenstein and Feng Zhu compared levels of political bias in Wikipedia and Encyclopaedia Britannica by quantifying each encyclopaedia’s respective usage of phrases favoured by Democratic or Republican members of US congress. Their study found that Wikipedia articles are more politically biased than those in Encyclopaedia Britannica, as well as being slanted towards Democratic (as opposed to Republican) points of view. The study also found that the amount of bias in Wikipedia articles tended to decrease the greater the number of people who had edited them. The reason for this trend was explained in an earlier study by the same authors: “Benefitting from the efforts of many contributors, an article is also more likely to present controversial content in an unbiased way: thus diversity may help reduce content bias.”"

"Wikipedia’s list of deprecated sources currently contains 16 right-leaning sources: Breitbart, the Daily Caller, the Daily Mail, the Daily Star, the Epoch Times, FrontPage Magazine, the Gateway Pundit, Infowars, LifeSiteNews, News of the World, One America News Network, the Sun, Taki’s Magazine, VDare, WorldNetDaily, and Zero Hedge – and just one left-leaning source, Occupy Democrats. Other politically biased sources have also been deprecated, but it is harder to position them on the left-right political axis, such as media companies controlled by the Russian or Chinese government. The deprecated right-leaning sources include both those that advance far-right conspiracy theories (Infowars and WorldNetDaily) and those that advance ordinary conservatism (the Daily Mail and the Sun), as well as many shades of grey between those two extremes. It could be argued that even the non-extreme sources that have been deprecated are not of a particularly high quality, so the prohibition against citing them is not a problem per se, but a similar standard has not been applied to lower quality, left-leaning sources such as CounterPunch, AlterNet, and the Daily Kos.

According to Ad Fontes Media‘s widely-used media bias chart (which is commonly cited in discussions on the reliable sources noticeboard), CounterPunch, AlterNet, and the Daily Kos are all less reliable than the Daily Mail. This is significant because the Daily Mail, a deprecated right-leaning source, is often used as a benchmark for judging whether other right-leaning sources should be deprecated. All three of these left-wing sources are widely used at Wikipedia. An external links search shows around 2,580 Wikipedia pages linking to CounterPunch, around 2,400 linking to the Daily Kos, and around 1,640 linking to AlterNet. (These search results include both articles and talk pages, because Wikipedia’s software does not have a way to confine an external links search to just articles.)

A proposal to deprecate AlterNet was made in April 2019, but the proposal received very little support. One user argued that AlterNet should be deprecated due to the site’s distribution of false medical information—that anthrax can be treated using homeopathy, for instance—meant that following its instructions can cause bodily harm. On the other hand, one of the users opposed to deprecation argued that AlterNet is “valuable for providing progressive viewpoints and reporting or interviews of progressive organizations.” The majority of the Wikipedia articles citing AlterNet are not medical articles, but in light of Wikipedia’s status as the most widely used source of medical information for doctors and patients, allowing citations to AlterNet poses a risk that does not exist for most of the deprecated right-leaning tabloid newspapers and political websites."