Use of the word is out of ignorance - not for intentional
disparagement - would be my guess. It's the Archie
Bunker syndrome.
From
www.m-w.com
Main Entry: in·fa·mous
Pronunciation: 'in-f&-m&s
Function: adjective
Etymology: Middle English,
from Latin infamis, from in- + fama fame
1 :
having a reputation of the worst kind
2 : causing
or bringing infamy : DISGRACEFUL
3 : convicted
of an offense bringing infamy
- Kirt
Blattenberger