A past startup had the same experience with Reddit ads. The initial replies were so negative ("I could do this 3x cheaper myself" etc), and often negative for the sake of negativity. It took a little time, but we replied to most of them with gentle words along the lines of "thank you for your thoughts and comments; we're a small business trying to do things ethically; getting it from us saves you the time/cost of leaving the house and we know how valuable your time is" - and it actually ended up quite a decent ad.
People just love to hate, especially when there's no human face to something. Or, I think in the case of places/networks where the community is tight and niche, if you're going to interject your product you'd better have enough of an understanding to answer as if you belong/have been a silent part of it all along.
Complete aside - I'm glad I've never had to market to devs, haha.