Your current employer should be considered an enemy to your well-being and you need to find new employment post-haste.
No company will have regulations which are all-and-always perfect for every employee, and some managers will be stupider in applying rules than others - this is a good exercise in learning to stand up for yourself and getting what you want without quitting. If you're a good developer, they'll be willing to "bend a few rules" to keep you.
I concur with the top comment: run, don't walk, to the nearest exit.
So true. Cogs cannot rectify. Therefore, either give up hope or switch to a context where you are not a cog.
It's surprising how far people can string themselves along refusing to admit this (cf the fantasy literature about "organizational change"). I did it myself for a few years before snapping out of it.
Having said that, I wouldn't expend too much energy on trying to get them to change their minds...
Excellent point. I believe that no matter the outcome, going on the record in a "direct-but-professional" manner is good karma. Worse case: it removes any ambiguity about the reasons for your departure. Best case: it gives you the opportunity to talk some sense into one manager, potentially improving the lives of a whole team of developers.
It's also good negotiation practice.
If it's as implied and they flat lied in the interview then change policy? Step 1 is ignore them, you're not doing anything illegal. Step 2 is find a new job immediately.
They are paranoid you will steal from them the ideas you code on and compete.
They want to own your ass.
In either case, I don't like paranoid management, and I don't like people "owning my ass".
Now on the flip side I don't see why someone you TRUST can't own the company. You might program for it unofficially while working at your current company.