I’m a native English speaker and had no issue… but I come across (or hear) contractions like “ain’t” often enough that it barely registers as being non-standard… just much less formal, really. Some punctuation might’ve helped you here.

Yes, it was very clear (native speaker here). Something like this is more commonly spoken than written, so I can see why it might be confusing. If your experiencing with English is more formal (via education, reading, etc) vs talking to a whole bunch of different people, that would explain it.

Was this easily legible to you?

Yes, very easily.

English doesn't have one standard grammar, but yeah this was pretty easy to understand for me.

"Ain't" can be kind of difficult. It can mean "are not," "am not," "is not," "has not," or "have not." Aside from that, the statements should be separated with a period, and "it's" was used instead of "is it." Also, they use "the fuck" instead of "what the fuck."

"Ain't" is pretty common in casual speech now, and the rest is relatively common in internet speech, so it was pretty easy to read for me.

"Capitalism hasn't solve white people's poverty. What the fuck is it going to do for us?"

I think the linguists call it African American Vernacular English. It's completely reasonable for you to not understand it from the outside looking in.

The main disconnect is they contracted "is it" into "it's" when "it's" is normal a posessive like that is mine, e.g. it's mine. Aka "the fuck is it going to do" or "the fuck's it going to do" would have been correct. At least I think so as a native speaker but someone with more knowledge on grammar might have more insight.