The whole point was we knew it happened at MintPal but did not know if other exchanges were next, in the next minute, the next hour, or the next day. So yea it was already too late and all you could do is wait it out if the attack was active at your exchange but at least you had the heads up incase you had coins at other exchanges and wanted the opportunity to move them before they got hit. We did not tell anyone to do anything we just gave them the info we had so they could take whatever course of action they saw fit. I personally moved a good chunk of coins out of Cryptsy that i had just bought a few days ago and had not yet sent to my wallet. Again it was speculated it was a 51% attack but it could have been a lot more, we did not have an in depth explanation of the extent of the attack at the time.
I really think it would be worth your while to read up on 51% attacks a little more.
The fact that Minpal reported it and cryptsy did not does not mean that cryptsy was not yet affected.
A double spend attack is not against an exchange it is against the network. it is only detected by the exchange when they notice unusual transactions. When the network has forked (which is necessary to carry out double spend) it is unwise to make any transactions anywhere on the network because they may fail (and you may not know for some time). Even trades you make on any exchange can be wound back if the exchange is found to be operating on the wrong fork.. (usually exchanges halt trading and withdrawals if this happens but not all exchanges are smart enough to notice)
telling the community "this is what I did but I'm not telling you to do that" is a moot point since people often do follow the examples people who they assume have some leadership role.
the bottom line is.. you got lucky and nothing you did after the fact would have made any difference to the outcome of that event.... you could have easily had your coins and or related transactions frozen on any exchange.
this is why eduction and preemptive action are so important.
people do make a big fuss about 51% attacks.. but as long as you stay calm and stay put they are relatively harmless to coin holders (people actually holding the coins in an address that they control)..
for exchanges and miners however.. it is a different story. for miners it can mean losing a few days payout... for exchanges it can be near fatal. (as was the case with cryptorush, coinmarket, vircurex and various others)