What do you think about the exchanges that increase the confirmation number for coins?
That's not a problem but we need more time waiting for our funds to be deposited into our exchange site's account.
Is this due to the demand by the company or platform itself in order to prevent possible attacks?
It's to prevent the possible attacks but this actually depends on what kind of coin. Each coin has different confirmation as requirements to make a deposit into your account.
Remember each party has a minimum requirement confirmation from the block that's needed to ensure your transaction has successfully delivered by the block or confirmed (that means the transaction really happens). I think that demand plays nothing in this case.
Can this method be used to stop these attacks?
It can but the attack can happen with some coins. It's not all of the coins can be attacked with the same kind of attack.