No it isn't. There is nothing admirable about Louis XVIII, his brother and his two nephews. They made a complete mess of ruling France in both restorations and were finally, and rightfully, kicked out by the French people. There is no double standard here. Napoleon is admirable in many ways, especially in leadership, as a civil ruler and reformer, and his military achievements. The only Bourbon in 1815 who did anything admirable was the unfortunate Princess Royale, who Napoleon dubbed 'the only real man in the family.' A harsh judgment, but also an admirable one.
The Bourbons were found wanting, as rulers, as men, and as a family. They had thoroughly degenerated from Henry IV, who was a soldier who led from the front.