Cut to the chase - the OP asked if he needed a slide out support. Are you stating that he does, or are you just upset that others feel that they could cause damage, and you disagree? Most people with no experience ask questions of others who do - and who's cumlative experience spans decades. The consensus here is that 98% of posters advise against using them
I like cut to the chase straight forward and to the point. 98% of the posters you mentioned have not ever used them or stated so here. That 98% are not giving there personal experiences with slide supports just opinions without experience.
I am not saying the opp needs them not knowing his circumstances but I am saying that the 98% that say they will cause damage have never used them, I have without damage and with the dreaded flat tire.
There's always two sides to every story. The opp has his options to choose for himself.
I just wished that on this forum the advice would come from actual experiences not guesses which rules on this thread!