I fully agree, I typed out three other replies before I realized you had already made each of my points better than I would have.

I have a really hard time pushing back on the social isolation based insults here because the most vocal people about being isolated are awful people for other reasons, and I don't want to sound like I'm just defending them.

loneliness in general is rarely if ever the sole fault of the individual, it is a social problem with social causes.

Which should be obvious with even the slightest bit of investigation! I find that a lot of people like to moralize about people who are isolated "deserving" it, despite how isolated people are unsurprisingly more likely to come from marginalized groups (wealth and disability correlate with social isolation in exactly the ways you would expect).