I would like to say that there are Gammas with a bad reputation. I did benchmarked Amber Heard as SEE and Martin Shkreli as LIE but they typically get caught later after all the damage have been done. I also think Donald Trump is an SEE but many would argued that he's SLE, and he seem to be hated by many.
I don't think Delta and Alpha are stigmatized in the real world though. However, both judicious quadra would be sometimes stigmatized in the Facebook Socionics community as being a useless joke who either play video games all day or carve wood all day and be boring (Spongebob, Fred Rogers, and Hank Hill). Sometimes, being a Beta in the Socionics community are overtyped similar to the "INTJ Mastermind" in the MBTI community. Being a Delta and Alpha is similar to what people think of sensors in MBTI and enneagram 6 in the enneagram community.