It's easy to shade Ke$ha. Not because she's a bad artist, but because she doesn't try to be/look/sound perfect (sound perfect purely vocally I mean) all the time to begin with. Of course she's serious about her art in general and about what she does as a singer, songwriter and performer, or she obviously wouldn't have gotten to where she is. But being perfect and always on-point and impeccable and just sterile as an artist (if you get what I mean) is not at all what she's about.
However that doesn't mean she's not a devoted and great artist....
Jeffsuxx and Yourfavefan have delivered the receipts you asked for. Now don't forget Ke$ha can show completely different sides artistically and to her persona. Must I add songs like
Animal, Goodbye, The Harold Song or Dancing With Tears In My Eyes to Jeffsuxx's and Yourfavefan's videos?
Also, she didn't even shade Britney here in any way, clearly no insult intended whatsoever. Just stop. Your hate is out of place and proportion.