My Response: This is a great question and one that could be responded to in a multitude of ways, all appearing to be correct to some and incorrect to others. This is because the word "Mason" is used in so many different ways that most people have their own way of thinking about it that is personal, subjective and specific, based upon their experiences.
To respond to this question with any credibility, you must first answer another question, "What is a Mason" and lay the foundation for the definition of the word. It is not until you define the word for yourself that you can then ascertain who may fit your subjective description.
While you are at it, you might also want to define, "What is a Freemason." You might assume that they are one in the same, and in certain situations your assumption as to the applied definition would be spot on. However, should you wish to treat these two words as separate things and know when one is not the other, you must additionally define, "What differentiates the two from each other?"
Although many might think doing this to be a fool's errand, I recommended that you do this anyway so that you do not confuse the two or anyone else trying to understand who is a Mason, especially when someone pretending to be one is clearly not the other. If you don't take the time to distinguish the two now and do so clearly, you could be easily fooled when the task is put before you.
My experience tells me that a man can be one and not the other. It also tells me that one is not necessarily a subset of the other and that being one is necessarily being the other.
All this is not understood by some and even dismissed as nonsense by others. I have found though that Masons tend to understand and respect this all too well. It is in their training; training that many Freemasons never get.
As you take the time to explore your own definitions of the two, how they are similar and how they differ from one another, you'll form your own conclusions and act accordingly.
Once you do take the time to do this, when you come across a Freemason claiming to be a Mason who doesn't see or understand that there are specific differences, be assured that they are most likely not what they claim to be.
If all this sounds a bit cryptic to you now, and you truly don't know who a Mason is, seek Further Light on it and in time it should become clearer. Your Seeking shall return great Benefits.
Brother John S Nagy