Your point is valid in some way but I dont think saying parasites to the hodlers is justifiable as everyone cannot do trading (may be due to lack of knowledge of TA or time constraints or some other reasons) so they want to be part of this space (for the sake of money may be not the tech behind it and to be frank most of the people here are for money if it was not like that then we would not have been seeing bitcoin at this level).
Parasites is the right term for those looking only for financial benefits via someone else doing all the dirty work for them, whether you or anyone else likes or not.
This is not the problem. Bitcoin or any other cryptocurrency may never make it as a means of payment, and that would be the real problem. It is quite possible that it will remain a niche instrument with a limited use, like digital gold but stripped of its gold aspect. In fact, this is what happening right now with altcoins. They seem to be losing their speculative component, but without it they are mostly useless, apart from a few altcoins like ethereum, litecoin, doges, which have their own areas of application, no less limited.