Bitcoins cant be hacked but we cant say anything
If it is on the network then it is vulnerable to attacks
Its next to impossible to hack bitcoins but the wallets can be
I think bitcoins can be hacked as it is available online and anything which is online is subject to hack if not properly taken care of. There are many hackers whom job is to get bitcoin hack so we need to be careful. Things like keep the private key safe and using 2fa for online wallets and exchanges are a few steps which can safeguard us from hackers.