Earlier quoted context omitted.
Problem is, you could potentially encroach on a big company's interests without knowing so, i.e. they're working in [insert space] in secret, or create an ethical issue for the company. Truth is, excepting maybe Netflix, the rest of FAANG requires you to get approvals.
That is entirely possible, but not at all a problem. If something is being done in secret, so that the employee doesn't know that the other division is working on it, then there are no trade secrets that would be divulged by working on something similar. That companies require you to get approval to work on something on your own time is fundamentally absurd. If I were a carpenter, I would not need permission to make…
So like it or not, if it looks like there're a conflict of interest (even if there isn't), people will blame it on the company.
So I don't really think it's so bad that they want to know what you're working on, provided that approval is usually granted.