That’s how Reddit works/worked. Probably lemmy too though I haven’t looked too close. Deleting your account doesn’t necessarily mean the content your account created is taken with it. Things not being deleted with your account is a werid thing to cite for spy ware, lots of stuff works like that and you can delete it, just isn’t automatically deleted with your account.

Discord having security flaws does not make it spy ware. There have been some pretty severe security issues but almost every one I’ve heard of has its roots in a gullible user running some sort of application on their machine or scanning a QR code with the Discord app which makes it extremely clear you are logging into another device… The only one I’m aware of that I found very concerning was iirc a werid video player vulnerability that could yank your token.

I highly doubt Discord is giving advertisers access to the messages on their platform. That sounds insanely illegal and also largly a waste of time cause if they are doing that it doesn’t work very well.