Can we acknowledge the harms of fatphobia without "well, actually"-ing about health?
Looking at those links, it seems that a lot of the "fat isn't so bad" science is making fairly small claims that are then overstated both by both sides of this argument.
For example, that second link is all about genetic variation. It's not suggesting "being obese isn't bad for you", it's suggesting "being obese isn't bad for certain people". It doesn't seem particularly relevant to the average person, who presumably doesn't have the genetic quirks in question.
And the research discussed in the third link, in some ways, actually affirms the common understanding that fat is unhealthy. It talks about a U-shaped mortality curve, in which being either too fat or too thin puts you at risk. That's 100% in line with the standard narrative. As far as I can tell, that part of the podcast is really just an argument that the top of the "normal" weight category should be extended upwards a bit.
I went looking for that U-shaped curve and found this:
and while it supports their claims, it also completely matches your experience in college. Because it shows excess weight being bad for your health! It just calls into question the exact point where it becomes a problem. (And of course, it's entirely possible that being fat makes you less healthy in ways that don't really affect mortality. Feeling bad sucks even when it's not going to kill you.)