I can confirm this.
I got into Beta in the initial round of 100 Safety Score peeps.
I have a Model 3 Performance, and did many, many launches. At the time, I mentioned this on the forums, and a guy said that he was "absolutely sure" that hard acceleration *was* counted against you in a super-secret section of the Safety Score. Surprisingly enough, he was wrong.
I'm betting I had 50 max power 0-60 launches, and at least as many full on max throttle quarter mile runs (it's nice to live in the boonies... sometimes). No effect on SS, and as I said, I got FSD in the first batch of 100 SS adds.