What do you think about the exchanges that increase the confirmation number for coins? Is this due to the demand by the company or platform itself in order to prevent possible attacks?
Can this method be used to stop these attacks?
Yes, it has something to do with security of that altcoin, because they can easily be get a 51% attack. Take for example Bitcoin Gold, they have been successfully attack before, and what did the exchange did? some of them delisted it. Even Bitcoin Cash was attack as well: (
https://www.coindesk.com/bitcoin-cash-miners-undo-attackers-transactions-with-51-attack.)
You can refer to this and see how many confirmations are needed for altcoins: (
https://howmanyconfs.com/)