I think the issue may be that many astronomers (and I count myself amongst them) do not like the term “amateur”.
If you look in the dictionary, one definition of an astronomer is “A person who is skilled in astronomy or who makes observations of celestial phenomena”.
This would include all of us.
Since many “professional astronomers” carry out reseach on data, and never look through a telescope, the distinction between “amateur” and “professional” seems somewhat arbitrary – apart from the fact the “professional astronomers” are presumably being paid!