Slavs liked to be slaves so much, that they forgot their own style of naming themselves and adopted Germanic word for "slave" as their name
What a nonsense!
The most widely accepted hypothesis derives the name from "слово" (word), AFAIK.

Here is the word "Slavs" written in different Slavic languages, according to Wikipedia:

Church Slavoniс - словѣнє
Russian and Belorussian - славяне
Ukrainian - слов'яни
Bulgarian - славяни
Serbian and Macedonian - Словени
Croatian and Bosnian - Slaveni
Slovene - Slovani
Polish - Słowianie
Czech - Slované
Slovak - Slovania