The other possibility, which still sucks mind you, is that they looked into compliance and then looked at the cost of doing it and said nope, not worth it. If BTC was at $100k and they were making 5X what they are now and they could have taken it a bit easy to deal with health issues and brought in a few lawyers and whoever to deal with the compliance and whatever else was needed. But it's not, and sometimes you just have to walk away. Would be nice if they open soured their code at shutdown so someone else could run with it, but on the other hand the fraud and scam sites that would start popping up would most likely be insane.
Any way you put it their reasons are certainly related mostly with regulations and compliance, but they can't go out any just say it like that in public.
Sure they could release source code but it's not some rocket science, and we already have similar P2P websites that works,
like LocalMonero, AgoraDesk, HodlHodl, etc. and they all have better rating than LocalCrytos on kycnot.me website.
Source code is also private for this alternatives, but advantages for LocalMonero andAgoraDesk are that No personal information is needed, no need for JavaScripts, TOR is available, there is API and Android/iOS apps.
That is much better than LocalCryptos, so people can just transition there.