Posting it to your audience of followers is not spam, but contacting the shotcallers and asking for help, not for yourself, but for the entire project is spam?
Yes, sending unsolicited requests to stakeholdres asking them to use their stake in a certain way is considered spam.
What is your opinion about deletions from the blockchain?
Whatever is entered in the blockchain is stored there forever.
And if a blockchain can not allow them (although I believe it can with a big enough consensus), then hard forks for the mere purpose of deletion if necessary?
It would require a hardfork to do this. I do not currently see any cases where I would personally support a fork to remove any content from the blockchain.
And the same questions and answers applied for elimination of stolen rewards (like what should have been done against zeartul) or clear cases of spam (checkthisout/grumpy, bernie and others I read about).
If users follow proper security precautions, their accounts and funds will not be stolen. If users do not follow proper precautions and lose their account or funds, it is not the responsibility of the development team and witnesses to correct their mistake. It actually puts the devs and witnesses in a dangerous position of authority to have that power, as many cases are not black and white, and could even be fraudulent claims.
Where informing about and asking to fight spam is considered spam, the situation gets to what it came to here.
The zeartul case is a clear enough case of a scam.
I am not well informed about it, but I think he was a pioneer of the "no refunds" policy, and he did get some fraction of an SBD from me, his bot did not vote on, and he refused to refund after I informed him about it and since then I knew not to use it and not to deal with him.
Of course trying to alarm others collectively would have been futile, ignored and considered immature in any case it would have been noticed.
Whose responsibility was the ETC case?
(Why) Does it matter whose responsibility you consider it to be?
Certain acts demand extreme actions, or else psychopathy is rewarded.
It is also burglary victims' fault that they were not sufficiently armed, trained and alert.
If it depended on me, I would have used extreme actions in less extreme cases than zeartul.