What's so confusing? It is just a bit of community fun. You don't have to send a greater amount, so it's not like it matters to you.
The only responsibility was on the person sending it to you to have some idea that you would 1. Find it funny and not bothersome and 2. Send it on to someone else.
Your comment about the point of crypto being to not have to trust anyone also makes no sense as it relates to the protocol and ownership of your own wallet and funds, not to what people and communities do with their money or resources.
I disagree. Such behavour develops more scamish vulnerability of the person. One day it is "I will send you sth, send it further, it's a nice game" and another day it is "Lend me some money, I will send it back later".
From me - big NO NO NO.
Yet you're fine with delegated proof of stake? Isn't that trust in 20 people? So, which is it?
But, you make a fair point. There was no agreement prior to the transfer. Personally, I wouldn't hold it against you if you kept it or did whatever.
I don't want to hold it. I don't need it.
Then either return it to the person who sent it to you, pass it to whoever else seems to care, or send it to @null for fun and as something that is actually good for STEEM
'Consent' is a wonderful word.
So is 'gushing'.... but that's not relevant right now.