I just signed the petition. In addition to possible market manipulation, I think it is hypocritical for a "green" company to hold bitcoin. This has hurt the Tesla image and lost them sales and market cap- https://teslamotorsclub.com/tmc/threads/tesla-backing-bitcoin-is-a-carbon-tragedy-energy-use-is-huge-transaction.220105/
https://mattelston.com/2021/03/24/teslas-bitcoin-folies/