Oh, I understand you quite well. I just think that someone who looks at the rules and thinks that they're screwed by them isn't getting into the feel of RPGs. They're a tool to set your imagination free, not lock you in a box. You start with the default rules and change them to suit you. If you read them and see them as chiselled in stone tablets, then you're missing the whole point.
That's a generic "you", in case that wasn't obvious
Changing to suit you, singular, is a lot easier than changing to suit the entire party including the DM.
Allignment especially, is always a game of what does the character see their actions as and what does the DM see the action as.
The DM creates the world and thus determines what the limits on allignment are. Hopefully a DM has taken his players into consideration and isn't just presenting his views as the only ones. However, even with understanding, it's going to be impossible to get a complete consensus. So, players will do what their character believes to be right, and then the DM will tell them they are acting against their allignment, etc, etc, etc ...
The number of threads and discussions about allignments basically shows how little people agree about allignments, etc. The same is true for play groups. Personally, I like the 4e system. I basically consider what my character is, and drop him into one of the three 'acceptable' allignment boxes for the PC. I know that when it was tied into the mechanics, it often meant deciding on the allignment when building the mechanical character, which meant you then had to develop the personality to 'fit' the allignment.
Another thing: Forcing a player to change their allignment in 4e doesn't really "punish" them. However, having people see them differently causes their actions to have consequences. So, instead of giving "evil points" to the PC, anyone that witnessed/knows of the act well ... knows of it. Some of the PCs may see it as a cowardly or evil act, while others may actually think it was a good thing. You could have an infernal pact tiefling who is actually lawful good ... BUT people are likely going to treat him as evil until he shows them otherwise. Allignment doesn't directly influence people's attitude towards you, but your reputation is influenced by your actions (not your motivation). The allignment of the person 'judging' your actions, on the other hand, will influence their attitude towards you.
So, allignment is basically a handy reminder of that characters (or NPCs) outlook towards the world, motivation, etc. Their actions will speak for themselves. If the PCs are renowned for their Dirty Harry style, they may be praised by the unalligned towns people who are happy that their city was saved at all costs, but the lawful good people of the religious order within the city give them a cold shoulder and see them as barely better than the threats they are dealing with ... for example.
I think the old idea of punishing a player for going outside their allignment, or 'forcing' them to change allignment were a little odd, as it basically discouraged character growth. It's one thing to act out of character ... another for the character to evolve. Now some things, like a paladin "falling" and having to redeem himself is something that has ties to the stories that inspired the class in he first place ... but you can just as easily have that kind of story without stripping the paladin of his powers, just having the paladin punishing himself (so a PC chooses to take on the 'quest' for redemption, and isn't having it thrust upon him by a DM that disagrees with his definition of lawful good). And with the more vague link between god and paladin, you can even have a "Fugitive" type situation where a paladin is framed as a heretic and has his own order coming after him and the party, even though he hasn't done anything wrong.