Just saying things "as a test" is indistinguishable from defending it online. Things like body language, tone and intent do not come across as easily.

That being said toxic people exist everywhere on the internet it's a flaw in our biology, we haven't adapted to communicating this way yet.

That being said there's a difference between a bad take like your above examples and condoning oppression and marginalization as some political groups have do.

One deserves to be defended vehemently.

The Linux thing, I doubt you'll get toxic comments. You'll probably get comments asking why to try to help, though that can always come off as demeaning. If you say Linux is bad, that's different. You'll likely get a lot of comments explaining why that isn't true and that it's a pretty ignorant take.

For the other comments, "piracy is theft" is, again, an objective statement, not a value judgement. Saying that is to say people who disagree are wrong. Same with the YouTube one. Change "good" to "useful" would probably be better way to say it.

There's a difference between comments that judge other people (which will likely get a strong response) and comments that judge the subject. It's something people frequently fail with. Even if it's worded well, people will often take judging something they agree with as an attack on their character, which is also not useful. Humans aren't logical beings.