You sound like the poor man who envies the privileged wealthy. Some people are born to privilege. Some people have to work for it. Thats the way of the world. Success is not always about how hard you work but more who you know. If there were a limited amount of XP in the game it would make sense to be angry at PLers. But there is not. XP, like monetary wealth, is generated not accumulated. The poor man tries to generate all his wealth on his own. The wealthy man uses the power of relationships and networking to get others to generate his wealth for him. The poor man works the job. The wealthy man works the workers. This is the way of life. Learn it and prosper. Or complain about it in poverty.
On the other hand, there is a BIG difference between someone who has worked their way to lvl 40 and someone who PLed there. The former knows how to use the toon in a very optimal way while the later does not. The former will be able to continue on his own without being PLed while the later will not (as effectively). The later was given a fish while the former made his own fishing pole. If you need to feel superior in anything you can value the skills that YOU as a player develop in playing the game, not the virtual skills of your toon. Bill Gates is very wealthy but I'll bet you that he cant write a flight simulator on his own.
The only way it effects you is that it may cheapen the hard work you put in if everyone thinks that you just PLed to the top like the rest of them. I think that is the real reason why you are upset. You want your work to result in something that is exclusively valuable. Well, too bad. You can work for $1M or have it given to you. No one knows the difference or cares. You need to change your values and stop thinking of the game as work or effort. If you just have fun playing it and dont focus so much on the XP then your experience will be much more rewarding. You cant change the world if you cant change yourself.