Nothing wrong with that, sure, but making comments related to ongoing antitrust litigation against company employing you, while not being any official spokesperson and not having your comments vetted by legal and PR, can be really, really detrimental to one's career if Google decides that it doesn't like your comments. Google is very explicit in its internal trainings to never make any public comments like that unless you're officially empowered to do so. You can say or write anything you want on HN... on the last day at your job.