As I understand it, the concept refers to reifying relationships between humans as relationships between things. Is this an example of that? People use this kind of stuff for the most varied reasons: long distance partners buy one for their SO, people online hand remote controls to roleplay doms... Hardly what Marx had in mind when criticising commodity fetishism ;)
Leaving aside how to apply marxian analysis to household relations, non-professional sexual partners, and so forth - the case of how people conceive cam sex workers using these things is an unambiguous example of marxian fetish. Your "human relations disguised as a relation between things" is laid pretty bare, there. That it also puns as "fetish" in a more conventional vulgar sense is just icing on that cake.