I have a serious medical condition. I have gotten off of multiple drugs, in part by getting very picky about what I eat. I am willing to eat pizza sometimes.

I absolutely do not need a total stranger deciding for me what is nutritionally appropriate for me, all Big Brother style.

You don't have to eat it, you can always bring your own food or eat something before/after. You're not "missing out" in the same way you're not "missing out" when you don't go pick up all the free junk on Craigslist.

Comparison is not accurate, not picking up junk on craigslist takes 0 time, tech event takes >0 time.

A comparison that isn't quite the same on one dimension doesn't invalidate the comparison... The dimensions I was comparing were those of temptation and of "missing out" on some free stuff. Still, not eating free pizza at the tech event take 0 time too. Maybe you'd argue that you have to eat sooner or later and food is already there so you can multitask it but by the same argument for many free X on Craigslist, you'll have to get an X sooner or later, it's already there so you can multitask picking it up while you go do some other errand. Or hey, ignoring Craigslist, look at that decent-looking free chair you're about to drive past going home from work...

Comparison is very accurate, not picking up free junk on craigslist takes 0 time, not eating the free food at the tech event (that you are already going to) takes 0 time.

But you get a tech event out of it, which is presumably the primary reason you're there.

Pizza is not a bad diet (only eating pizza is bad, but we are not talking about that).

Has a decent mix of protein, fats and carbs in a tasty package. Not everyone wants dry lean chicken, or zero-calory veg/shrooms, even if any two people here could agree on what is “nutritionally appropriate”.