^Usually when it is an overdose like some are assuming, there is normally mention of the pills or drugs that were found there. When Heath Ledger died for example this was the case. There has been no mention of this with Cory, so my gut says it wasn't. That doesn't mean it wasn't obviously, just that what we've been told, like you posted, doesn't suggest that it was.
Why do people feel the need to state they never watched Glee or didn't like it.
The number of times I have heard 'I don't like Glee but RIP Corey' If you hated Glee don't offer your condolences as thats all he is was really known for.
Get off your high horse. People are allowed to feel sad about a young person dying, whether they'd seen the show or not, or even if they didn't like it. It's possible to realise that an actor is a nice person but not like the TV show they were on.