It's because these are the rare butt-back cavemen

This must predate the fateful incident

What was the prompt/model?

Election season is coming up and people are upset that he's supporting genocide. He's trying to buy popularity instead of earning it by... you know, telling Isreal to stop committing genocide.

Arr shiver me kittens

Naw, Hamas isn't shitty enough for Elon to like them.

No but one of Mary Anne MacLeod's did

What? No video of the Italian dog bark?

Is part of their advertising budget. The people running are a captive audience they can advertise to and their logo can be on the tee shirts the runners receive.

If you wear that shirt later that's more exposure for the money.

So the answer to your question is its the same reason you might buy space on a billboard. Instead of giving those dollars to a billboard company they're giving it to the cause and getting their name plastered all over it. If it's effective they'll keep doing it.

They get sponsors for the event.

Well I don't know that