"How many kids learn there's help for them from these kinds of booths and activities?"

Not many. Pride events are not how the agency does its outreach.

However, and this is a BIG however, Pride events are an important source of donations and volunteer recruiting. This is going to have a significant, though certainly not crippling, impact on their budget.

I'd name the agency, but their executive director has asked me not to, out of a strategy of not encouraging the people making the threats.