Honestly, I don't understand why there's a rule against it. If someone has good intention to bless others with a raffle or freebies, it shouldn't be stopped.
That's most probably because any low value project would start making such giveaways - for advertising purpose - handing out some shitcoins or tokens with no value.
It's easy nowadays to camouflage bad intentions as good intentions. I guess that this is the way many scams actually work.