The last time I looked passengers can decide which airline they want to book on and are entitled to their opinion, personal minima if you will. This being the case, Radeng doesn't have to fly with anyone and doesn't have to justify it to anyone, so itisn';t a silly comment.
Good on BA for stating a resonable policy, now all they have to do is make it work. Suspect the staff dealing with the chaeckin will behave like Mk 1 Mod 0 humans and get it right most of the time, the passengers will behave like the passengers and most of the time it will work out. What BA (and the pax) need to worry about is the close calls on whether someone is "rude" or "abusive". Without a really well defined criteria for staff to use this should leave BA open to some really horrendous lawsuits. There will be suits anyway, but BA will be on much better legal standing if they have a very clear and uniform policy that they can prove is uniformly and impartially applied. Can't you just imagine the checklist?
1. appearance on one to ten scale
2. alcohol/drugs (tick yes or no, if yes how many sheets to the wind)
3. Rude Language- F*&#%#, S*^(&, etc. More than 5 usages in 2 minutes and boarding denied.
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could get really silly, but should provide for safer and more pleasant flight for all concerned, and is to be commended.