Wrong,they were the victims of their own weak security and lack of seriousness in protecting their clients' funds, every POW coin is subject to being attacked, there is a little to nothing that can be done about it on a code level , some methods like the "delay function" proposed by zen may make the attack a bit harder and that's all about it, the biggest part of responsibility is on the exchange itself.

There are many reasons why an exchange like Binance dominated the market in 1 years while Livecoin has never been top 10 or even top 30 despite being in business for years ,Security is one of the most important reasons.

if you go back in history and compare how every other exchange handled the 51% attack on MONA or any other 51% attack, you can easily see that Livecoin can easily be put on the top of the "suck-balls" list, Livecoin don't know how to run an exchange  -  simple !

tl;dr IMO Livecoin is not scam per se, but when investors lose their funds due to terrible security measures, it does not matter how you label them - they are as good as scammers, one does not have to directly steal your money, locking you out of your funds for saying stuff about them on Twitter or being too bad in protecting your funds are some great ways an exchange can follow to be considered a scam.