I've never read or heard of someone saying "the reason you're depressed is because of <insert minority group here>".
Oh so, you never heard of Incel or /r9k/?
"Women won't fuck me so they are all tooths who would rather fuck Jamal instead of me."
Or really, they just blame the jews in general for everything.
But you are right, the amount of cries for help on oldGaf or Era is more likely a result of the volume of users combined with the large visibility of the forum. If people are going to make a cry for help, they're going to make it to as large an audience as possible.
Left wing encourages getting help for mental illness and not being ashamed of it. Right wings communities like Voat, /v/ and r/Incel tend to foster it and and discourage getting help. They are also way more insular and don't have 4 forums stalking their users to make "points".
Incel forums literally tell people to not get help, because it's useless.
In short, you don't know what the fuck you are talking about.
But Averon is right as well, Era draws people with a particular mindset, and if you took a random sampling of era users and asked them if they identified as being depressed, I can't imagine that the sample rate would be in line with the national average.
Average compared to what?
And what's the final argument here? People don't magically get depressed. They often do it because of circumstances in real life. Of course I don't expect people who spend their life laughing at those people to try to emphasize with them.
4chan and Reddit are also much more random, compared to say looking up 'OH GOD THIS IS OFFENSIVE' videos on YouTube. As it will just recommend you more of such videos.
Bullshit. Places like /pol/ made a whole identity at being offended at the existence of gay people are black people. The only difference is that you think it's normal and acceptable. You laugh at Era while the whole conservative Internet throws a fit over Far Cry having two black girls on the cover until they find out they are villains, then they are OK with it.