Something I kind of noticed, in stark contrast to here.
On progressive Christian subreddits: Basically doesn't exist. If anyone expresses discontent with Catholicism they immediately get told they should just convert to Episcopalianism, there's even memes about that. No one ever brings up the "cultural" aspects or whatever or thinks it's strange if someone makes a full break from it.
On r/Catholicism: Basically exclusively hard right trads, no purely "cultural" people or anyone remotely liberal at all.
On r/Christianity, (probably the "centrist" place): Also doesn't really exist. The Catholics there still tend to be very conservative and if any more liberal people express discontent then the Episcopalians and other mainline church members come in and promote their own and ask them if they've thought about converting, and a lot of those members are openly converts from Catholicism themselves. No one finds this unusual or some sort of deviation from "how things work."
On secular and atheist spaces: duh, do I even need to explain? Pure 100% neckbeard atheism, no respect for any type of religious institution or cultural ties in any way whatsoever.
On general progressive and "social justice" oriented spaces: Basically a combination of the progressive Christian spaces and atheist ones, either they say you should convert to Episcopalian or another liberal church or that all religion is nonsense anyway, etc. No one ever defends Catholicism from a "cultural" perspective or makes the frankly bizarre in my view argument (that I've actually never seen anywhere except here come to think of it) that converting away from Catholicism is somehow inherently non-progressive.
And I know that Reddit has various stereotypes about it and not a very diverse user base but that's also true of here...and as a much bigger site I'm kind of surprised to almost never see this mentioned or bought up while here it's often assumed to be "the rule" and some people view that type of free conversion as really weird.
How is it bizarre at all?
Catholicism is a religion generally practiced by POC in Latin America and Africa; and led by a POC itself (Pope Jorge Mario Bergoglio). Trying to convert someone away from catholicism is therefore POC religious erasure and demonstrates a deep belief into white supremacy. Redditors should check their priviledge, and those Christian subreddits you mention should be banned for demonstrating white imperialism vs Catholic POC.