It's always annoying when organisers are coy about medals. There's a race local to me that I've never done because they never explain whether everyone gets a medal or memento or just the winners. It's 10 miles which is quite a lot for me, so if I run that far I'd like a medal even if I don't win. SPELL IT OUT.
To be fair, I think that particular race has finally said everyone gets a medal this year.
In fact I remember someone commenting on me once. I wasn't oversized but I was wearing a pink oversized event t-shirt (occupational hazard for XS women when the only t-shirt left is a unisex M). I heard someone call me a running marshmallow. I didn't wear that t-shirt again! Fortunately a lot of events size their t-shirts a bit better now.
I think some oversized people do get abuse if they just go out for a run around their local area. It's utterly ridiculous - there they are, out running and trying to get fitter and they get ridiculed. It's clearly better for them to sit on the sofa at home eating cake. Idiots! So yes I agree that parkrun is a safe place for them to run.
I don't think it's a silly question. And in fact there's an England Athletics survey out on injuries in runners which asks what level you are. If you don't know, you can't fill in the survey as it's one of those silly ones that you can't progress on until you've filled out the first page. I wish surveys would let you see the whole thing.