The name originated in the late 1850's, mostly in the upper classes of Southern England. But as times have moved on in England, then name has gone down hill and is now related to being
straight but very camp. Also the word Finnigan can be associated with bad sense of fashion, buying clothes from the other gender.
In addition to, the word Finnigan can be asscoiated with liking
people with wierd names e.g.
Arsenal, Chelsea