It's not your fault at all, I am also confused what exactly caused them to adopt such a hostile tone.
I have noticed that many Lemmings have a strong preference for explanations which emphasize the dysfunction of capitalism as the ultimate source of all worldly suffering. Your suggestion that even in the absence of capitalist incentives, running a modern healthcare system is still an incredibly expensive endeavor that must be funded somehow, disrupts that worldview. Thus, the hostility.
You could also try the Scaled algorithm, which was recently added with the new update. It's supposed to adjust for the size of the community so that the posts from large communities don't overwhelm your feed