cavu
You were fortunate enough to be allowed to sit on the flight deck of a BA aircraft for landing. You repaid that favour by making snide remarks about the crew, including the highly derogatory suggestion that they may have been hammered whilst on duty.
If you genuinely believed that, then you should have reported them, immediately on arrival in the UK, to BA, the CAA or the Police, for them to investigate.
It appears you didn’t, and instead chose to make your remarks anonymously, presumably to avoid having to substantiate them, and to minimise the risk of being sued for defamation by the crew concerned.
Fly Delta by all means, but I doubt if any of the Delta pilots I've met over the years will think any more highly of your behaviour than I do.