Well the difference between the two stories is that Dexter never said that he had taken part in rodeoing..he was explaining what it was. Even the star couldnt twist it to make out he had actually done it.
The Sam thing is a person who knows him selling a story.
I dont personally think there is anything to EITHER of the stories tbh. The Dexter thing was clearly blown out of proportion for the sake of selling papers (because we would have seen the warning if it happened) and I suspect the landlord just wants his 2 mins of fame by doing this, but the situations are not really the same.
Plus people who dont like dexter have been using this 'rodeo' thing (with nothing to back it up) for weeks now as an attempt to discredit him anyway, so this is nothing new