Is it important to be a co-author when PI takes first authorship on your work?
I don't see any logical reason why you should withdraw your name from the authorship list. This only hurts you in the long run. You should want to have credit for your work.

You might politely ask your advisor why the "guest authors" have been included, and what contribution they have made (since you said 60 percent was your work, what about the other 40 percent), and then discuss it further if you don't like or aren't satisfied with your advisor's answer.