Stonewalling, delaying and simply not responding can be so much worse when they play out in real situations than people might imagine. You can waste a lot of the other person's time this way. We might hear a lot of justifications like "whoops" or "volunteers!" but the supposed deniability of such tactics is part of what makes them so exasperating and emotionally draining to deal with. I will withhold a final judgement until hearing the other side but it really looks like the PSF has a lot to answer for here.