I would say not rude if explained the right way, and not in a pm
For myself, i did say respectfully it is kinda high priced, but still a good scope, and being honest with the pricing doesnt hurt, if done correctly, the OP did not make any comment and pushed it to ebay
Time will tell if he's right or wrong ... he's added an make an offer option .....
I've seen good stuff on Ebay having an hard time to be sold after so many "put it back to auction after many attempts" because the pricing was not right.
just a matter of doing some homework to check used stuff pricings ... and get an general idea of asking some selling price.
I tried to sell an fluke 105 serie II scope here, it was not a success, i pushed it to ebay at a very resonable price and was sold, the price was calculated slighlty higher because of the ebay fee's