I fail to see how "his pub, his rules" would apply when "his bed & breakfast, his rules" would not. Oh silly me, we're talking about law aren't we so no point in expecting it to make any sense.
ah yes, would he have asked a heterosexual couple kissing to leave ? How about someone snogging their dog. Or maybe a necrophiliac with a corpse playing tonsil tennis. Ah what a slippery slope when one tries to ban sexual behaviour in the public house.
Perhaps it would be fair to say heavy snogging is over the line, a quick peck is acceptable affection. But getting agreement on where to draw the line wouldn't be easy. It's all subjective opinion.