"har har veganism is dumb amirite? BBQ rules!"

dude

one of the main characters of this series is very famously vegetarian since 1995.

Paul McCartney, just as famously, requested that this be a permanent change as a condition of his guest starring role that episode.

Lisa Simpson has never wavered in her beliefs at any point in the shows three-decade-plus history.

this is not whataboutism, it is not "oh but look at this minor character who is still vegetarian" - it is Lisa Simpson.
a series lead and the main character of this episode.

and he's fat there because he is fat in real life - like, exactly as fat. they took his shirt off to highlight it but that's what he looks like now. he glop.

also the image of him eating BBQ was clearly that character saying fuck you to his fans, which mirrors reality even if real Morrissey may not have given up on being vegan. Lisa's reaction to it is to feel betrayed by her new idol, which is appropriate.

you really seem to be digging for something to be outraged about and this is the exact length i am willing to go to engage with that.

i understand where you are coming from if you are vegan but, and i cannot stress this enough, a series lead has been very famously vegetarian since 1995 and has never once wavered or shown it to be "just a phase."

please, have a good day.