It has everything to do with mixer in my opinion. The argument has always been centred on the legitimacy of the mixers and how they allow criminals to get away with stolen funds. I have no problem with them running their services whichever way they want but in an obvious case like this very one involving bybit, Secondly, the issue of multi sig wallet being hacked is not longer surprising, this is not the first time it's happening. The same way we are improving our wallet security is the same way hackers are developing alternatives to breach the security protocols.
And finally, don't entrust your coins to anyone or entity. Always remember not your keys, not your coins.
You have a point.
But just as the news headline says "Could be headed for Bitcoin mixers", which means even if the hackers choose not use a mixing service, there is already a theory in the minds of the public that mixers are primarily used to transfer illegal/stolen funds (which isn't far from the truth though), and doesn't make much difference.
And just like you've said, "it's crystal clear that they genuinely support illegal funds to become legal using their platforms". Which you and I already know. So, even if the hackers ends up not using their service (which is not certain), it still doesn't add anything meaningful to their reputation.
But I would have been more interested in a news headline like: Bybit got hacked, are customer's funds still safe on centralized exchanges?.