Some think it's dishonest. I think they couldn't think deeper.
One main reason, would be due to the fact that social medias love to block, ban, delete contents/accounts of people whom they disagree with. In that case, I would either need to keep a local backup of everything I posted/followed/saved/etc. or simply have various personas which I monitor to be as consistent as the social media's "policy" as possible. So, time and energy saved, is a wiser move.
So let the shallow thinkers play safe or have their time wasted.