In general? Yes. But it depends on the nature of the startup. VC-backed startups are not more trustworthy at all.
However, there's a rather huge difference in the capacity for harm. If Joe's Tiny Company is just as nasty as the likes of Amazon/Facebook/Google/etc., JTC is still preferable simply because they don't have as much power to abuse.
Startups are even worse - most seem to care only about growth, not even profit, their goal being to hand off the hot potato they built as soon as possible, to whoever gives enough money.