In Russia and Ukraine it seems to be not so by the mere fact that for today it is the only name for Pole. Formerly in 17-18 centuries Poles were also called Lachs but this is quite an obsolet for today Russian and Ukranian languages.
Not only by Ukrainians and Russians but also by Turks and Tatars... Well generally by our eastern neighbors and Poland was very often called Lechistan. For example king John III Sobieski was called "The Lion of the Lechistan".
I've often wondered about this. I would assume, following the rule that made "Paki" offensive, that "Scot" or "Jock" will become offensive and therefore not "PC". I know people who find "Jock" an offensive term towards Scottish people but I do not think this is offensive. Its actually Scottish for "John" so probably is on the same line as Polak at the moment.
Basically words are just words, it's the context in what their are being used that determines if their are going to be considered offensive or not. It would be a pity if the word Scot would also become an offensive word but sometimes we just can't do anything about it. :(