are Ellen DeGeneres, Jimmy Fallon, Jimmy Kimmel, etc. consider as "interviewers" even though they ask questions in their shows? tbh

Yes they are interviewers ...

In an interview, the reporter asks questions and the interviewer responds and that's basically it.

talk show includes interviews but also additional things like:

monologues

a music band

games played with guests

music performance by guests

a promotion (a new book, movie, record, etc) by the guests

and also games and interactions with the audience