Funny, just a few hours ago I was telling a friend that I noticed the opposite. This conversation started because while r/antiwork and r/work_reform had mostly incompatible ideologies, with antiwork being more radical, Lemmy suggested to me a community titled "Antiwork/Work reform" which is noticeably more status quo compacent. Additionally, the rate of posts going "capitalism isn't that bad, actually" and "fuck tankies" in my TL is higher than in Reddit.
I think this has to do with the amount of active users. If, say, 2% of active users are very vocal about abolishing wage slavery, if there are like 1000 users, that 2% is just 20 people, which wouldn't make a very active community, whereas if it's 100 000 users, then that makes 2000 people who can already make a sort of "echo chamber" where they can openly and actively discuss their ideas.
Also, not to forget that Reddit, like all mass social media, has algorithms meant to maximize your session lengths and that usually involves exposing you to more extremist ideas, both left and right.