His deception is shitty, but there is nothing wrong with joining a dating site to make platonic friends if you’re honest and up front about it from the beginning. I can think of zero other ways to make friends on a one on one basis, and I want more people to understand that group activities just don’t fucking work for everybody.
There are a ton of introverts, socially awkward or anxious people, neurodivergent people, folks who don’t want to risk getting COVID, and others who just genuinely don’t enjoy doing anything in groups. But pretty much every meetup and platonic friend making website out there revolves around group activities. Until we have a better way to meet potential friends one at a time, I can’t think of a better way than using dating apps for this purpose.