There are several connotations related to the term "Professional".
It may be used when referring to someone who does a certain job for money.
It may be used when referring to someone who has a job with which having a college degree or higher is the norm, such as doctors, lawyers, accountants, people who were suits, etc.
And it may be used when referring to someone who has attained a very high level of expertise in a certain discipline.
Or, evidently, it may be used when telling someone they can't be a professional because that person uses a certain type of equipment. This perception may or may not be caused by some degree of ignorance of the aforementioned equipment, or the use of it.
I'm a professional entertainer who uses arranger equipment. I'm not sorry if I don't fit certain criteria but, I do make money doing it, I do have a couple of college degrees, I often wear a suit, and have attained a fairly high level of expertise in my chosen discipline.
But still, many people who play guitar and/or sing, and play a little on weekends when they are off from their "real" jobs, find it necessary to criticize my choice of gear. Go figure.
And as Forest Gump said, "That's all I'm gonna say about THAT".