I’m sad for you to have been diminished and humiliated at the same time by a troll who works for Squarespace. It does sound like the company chose her version of events.
The guy thing is harder to comment on as it pertains to your private life. It factored into your job success and ‘The guy’ threw you under the bus to save his own butt it seems.
You are not being too sensitive.
Beware, there are cut-throat competitors in this world.