Earlier quoted context omitted.
This suggestion is mainly directed at newcomers to the industry, who may not have the reputation or experience to be able to credibly push back on many points of their employment agreement. Once you're in a seller's market for your level of skill (as I'm sure you are), you don't need this advice anymore and I'd encourage you not to let your employer restrict your moonlight projects. But particularly if it's your firs…
It depends on the state. In California, for example, Non-completes are notoriously unenforceable. I'll sign whatever illegal documents you want me to sign, knowning that they don't matter. You might respond by saying something like "what if they go after you anyway, even though it is unenforceable.". But the problem is that they could just do that anyway, illegal contract or not.
The difference is that with an illegal contract, your future employer might actually believe it's more headache than it's worth to fight. I would err on the side of casually striking it out of the employment contract, simply saying "this part of the standard document doesn't apply in our state" etc.