That's not thick though. That's a well thought out ethical position on whether art or ecology are most important and what kind of protest would gain most attention.
It's based on facts about the way oil is impacting the world we live in.
You just don't happen to agree with their analysis, or their priorities or their way of protesting.
However, what makes people who are anti immigration open to the charge of being "thick" - not that I think they are thick, but there is a charge to be met - is that they aren't drawing on accurate evidence and are being swayed by emotive tribal rhetoric. It's a lack of insight which often goes along with unpractised skills in abstract thinking.
I don't think working class people are thick at all. In fact I think most of them/us have been treated shamefully by late capitalist interests - tech companies, finance companies, housing policy, the financial markets, and by successive govenments who have drained the life out of our communities and made public services a hollowed-out transactional shell. People want good, warm, community solidarity for them and their families, and people to engage with them and help them as part of our shared welfare state, and they don't have it. They are quite legitimately looking around for who to blame. It's not a "thick" response to do that. everyone does.
It's a tiny bit thick, though, when someone with some knowledge says "hang on, those people aren't the problem, here's some evidence of the bigger picture" to just ignore it.
Problem is, no authorities are trusted now to provide any evidence of anything.