We had a great experience at 2 CO state parks while camping there last year. YMMV. The 2-pass system can be improved upon, but it works and the policy seems clear.
I don't have any problem with out-of-staters paying a bit more for their use of the parks. I'm sure a portion of state parks budget is paid by taxpayers in that state through the collection of other taxes, like income tax, sales tax, etc.
What I object to GREATLY is the OP's statement "good thing I don't carry anymore". I am a big pro-gun advocate, but that statement is reckless and casts a bad light on the 99.999% of law-abiding citizens who carry.