Personally, I think that modding games should be no big deal. Once I legally purchase a game (or any other program), I should be able to modify it in any way that fits my needs. If I do not care for the in-game music, I should be able to replace it with something I find more suitable. If I wish to (as GOODGOTD pointed out) modify the levels to make them more challenging, I should be able to do that. If I find a splash screen particularly annoying, I should be able to remove it.
Don't get me wrong. I am not asking to "crack" the game so that I can sell it to others illegally. I am just looking to extend the life of a game that I enjoy enough to purchase for myself. If more games would include good level editors or allowed you to change the music, much of this would be a non-issue. Besides, cheat codes (and discs) are legal and perfectly acceptable to most people. Why should making a game easier be acceptable while making it more difficult or more aesthetically pleasing be unacceptable?
If it is a matter of a person needing to rip apart the code to change things, think of it like a car. I buy a brand new Mustang GT. Should I be allowed to modify it to go faster? Should I be able to change the paint on it? Should I be able to change the radio? All of this is perfectly legal (within reason) under US laws. It is considered my property, not Ford's, to do with as I see fit. I also know that if I screw it up, it is all my own fault.
The same should hold true with anything that I buy. The first hackers/modders to jailbreak the I-Phone probably bricked quite a few $400 phones before they succeeded. They knew the risks and were willing to live with the consequences. Ultimately their ingenuity helped make the I-Phone more useful for their own needs. I am sure a similar process went into modding Tempest back in the day. Thanks to people with much more knowledge and skill than I posses, I can change the music on this weekends game giveaway (Trio.) That is a godsend considering how banal the music is/was!
As for how you state your title GMMan, I think that is up to you. Most of us here know what you mean by it, but remember that it has taken on a rather negative aspect in recent years. I lived with the moniker "D**n dirty hippie" for years before it became relatively acceptable again. Hopefully the same will be true for "hacker."