Public statements of support from its CEO for a regime actively weaponizing technology to build a mass-surveillance state.

Removing its no logging policy after being compelled by court order to log and disclose a user’s IP and browser fingerprint.

Personally, I gave up on Proton after they amended their TOS to include a mandatory arbitration clause, including a ban on class action lawsuits. IMO only the dirtiest of corporations rely on mandatory arbitration clauses. Without the spectre of a class action lawsuit, if a VPN were to get caught breaking its promises to its users, the only real damage the company would likely suffer would be reputational. These are for-profit corporations. The only way we can hold them accountable is to put their profits at risk.

edit: looks like @oce beat me to it