Yes it is. If a company is making its employees sign unethical agreements, then they deserve any negative consequence to that.
Don't make your employees sign unethical agreements, if you don't want people to lie to you, and screw you over.
Unironically, companies that do this, should be named and shamed, and everyone should take every legal option that they can get away with to screw over the company and the people who are making these decisions.
> It's better to simply strike out that line and say it's not valid in California so why have it in the contract.
Nope. Screw them over instead. They deserve it. Its legal, and they deserve to have negative consequences on them.