I'd be quite careful of making these sorts of posts, towards or for a specific group of people. I'm not a mentor myself, but even I know when there is a time and place for certain grievances to be discussed.
I can think of several times both mentors and not-mentors acted poorly and 'hurt' people. The furthest this topic should be going is reserved to Tickets for the staff to handle if the cases are pertinent. You've clearly had a run-in with a poor representative, and I do empathize, but this is bordering on the verge of hate-crime. Be it sprout or mentor, everyone should handle their grievances privately or with the proper people and not fan the dirty laundry to nurse misery.