1. The fact Poland got more MEPs as a bigger country and that bigger countries get less MEPs per eligible voter to protect the smaller ones are absolutely obvious. I'm not sure what you are even "picking" here, the point is that with low Polish turnout and high number of MEPs Poland puts in a Pole makes more of a change towards the EP composition that a Belgian does so he should be more likely to vote. MEP per vote (per vote, not per eligible voter) is actually higher for Poland than it is for Germany and Belgium because of this low Polish turnout. This should incentivize Poles to go to vote at least as much as Germans do but it doesn't.

2. Nowhere did I say it's a Poland exclusive thing and it's irrelevant to the argument. You are the one that made a sweeping generalization about why people happen to vote in general so all I need to provide is singular examples to disprove it (which I did).

3. That's completely irrelevant to your claims about how people are more likely to vote when it matters to their daily life or makes a significant change about the end result.

4. That law is not enforced (according to Wikipedia), if it were there would be a 100% turnout, not "just" 90% and even then the laws are what the society wants (more or less) and the same society can get rid of such laws if it doesn't think them right or boycott the vote itself using invalid votes - the secret ballot protects them in that case. Instead they vote and invalid votes percentage is as low as it is in other countries and not extraordinarily high.

You are free to use Germany instead of Belgium if the dead law about mandatory voting is so important to you. Turnout for EP was 48% in Germany where there are no such laws and 30 million Germans picked 96 MEPs, giving 0.3 million of voters per MEP, while Poland had 0.14 per MEP with 7.5 millions of voters picking 51 MEPs. Germans who (individually) affect the outcome less and who are in a much stabler situation in general due to Germany's own strength and location went and voted more numerously than Poles.

You also absolutely ignored how Poles care less about out national "winner takes all" vote than Germans do about their (comparatively) less important Federal ones (that are also among a bigger group of eligible voters, thus making each single German vote count for less than a Polish vote does for how each country is ran, in addition to unitary vs. federal split and German stability and Polish volatility) or how Poles vote in their own important national elections only as often as Germans do in very much comparatively irrelevant to them EP ones (and they are twice remove from EU affecting them via their own Federal and Land governments while Poles are once remove via our parliament and much more vulnerable to any EU fluctuations because we are smaller and in worse location as a country on an EU border).

Poland and Poles are often at odds with EU, Poland in vulnerable EU border position, Polish national parliamentary and presidential elections always swing the result and the outcome is absolute because Poland is not a federation. Pole should vote like crazy in all these elections but they don't so clearly just the fact a vote affects the outcome stronger (which Polish vote does compared to a German one) and that the voted on topic affects the the potential voter more (which both EU and national elections do to a Pole more than they do to a German) are not as relevant as you made them out to be. There are clearly other factors at work here in more significant ways that cause these differences in participation between (i.e.) Germans and Poles (maybe attitudes from the communist past, short democratic history or being relatively fresh EU country, I don't know).

Your points about how people are more likely to vote if it affects their life or about how there is less participation when a vote counts less towards the result are still both completely invalid because there are clearly other factors (that happen to make Poles vote less than Germans do) and you are now nitpicking, arguing semantics, changing the topic and listing all of the irrelevant and wrong nitpicks you can find and saying it's "one random section" to make it seem like if my entire wall of text was all wrong, which it wasn't.

I am done wasting my time replying to someone who argues in a way as disingenuous and cherry picked as you and I will not read your next reply.