Removal of tonsils in most of my boomer adult friends. Why did they do that to us kids?

Pressing reality. The push to avoid the dreaded tonsillitis had been commonplace for a hundred years, before antibiotics & general anesthesia. It was a socially acceptable approach to a frequent problem & we had little research to counter demand, similar to bloodletting & purges. Once the process was studied & detail & we understood the immune system better, the docs pushed back.
Tonsillectomy. I'm not sure i understand your question. Sometimes in the past tonsils were removed without the restrictions of today (some related to insurance more than medical reasons.).
Meant well. That was before evidence-based medicine. Doctors could perform procedures and get paid before proving that they actually helped.