Now a lot of people have said this poor drone could not possibly understand the situation well enough to not make statements that are flagrantly anti-competitive. Well, that is Google's problem. Both their automated system and their customer service are behaving in a way that hinders competitors. If they don't fix this, they are liable.
And by the looks of it, it has happened before, so there is a pattern.
I picture the setting in my mind and it's the best explanation. Someone sitting in a cubicle or a farm, answering thousand of messages like that per day. He's not reading the chat, he's scanning it for words like "ok", "thanks you", "fixed", "working now", "bye", etc.
Matomo doesn't register on their radar.
The user doesn't explain what Matomo is. His message looks like a copy/paste from matomo's website. It's even put into quote.
This conversation was not around Matomo being an alternative to GA.
Doesn't mean Google doesn't actively classify matomo as malware though.
The Google Rep was clear it was not allowed also (though perhaps misinformed).