Yeah, obviously a few people are bitter or delusional (see: every football forum, ever), but I think most accept that it was definitely a pen. You can go to any fan forum and cherry pick people with stupid opinions.
We definitely got the short stick with injuries - even if you try and argue that United have had the same level of injuries, you've got to remember that 'smaller' clubs can't afford to have as much quality sitting on the bench. Players like Fred, Mata, Bailly, James, Ighalo, Mctominay are far greater than what we have to play if we get injuries. You might complain about Bailly, for example, but it's not the same as having to play a 36 year old Wes Morgan, or Ryan Bennett.
That being said, it wasn't injuries that ultimately did for us. Ok, it didn't help after lock-down we lost a huge chunk of our first team, but our bad form started well before that.
I posted in another part of the forum, that I'm not too upset though; I'd used up all my anger by Watford and Bournemouth. Once that had happened, it was a near certainty that we'd thrown it away. The only thing that surprises me is that we somehow managed to keep a Europa place.