“Realtor” Should Be Capitalized? What?

(I’ll preface this post by saying that I live in the US.)

So I have to share this Merriam-Webster tidbit. When you search “realtor” in M-W, the only result that comes back is “Realtor.” 

That’s right: it’s capitalized. 

The definition M-W gives is “used for a real estate agent who is a member of the National Association of Realtors.”

So this means that (according to M-W) *every* “Realtor” belongs to this association? 

And if they don’t? I guess they’re just considered a “real estate agent?”

M-W’s listing for a “real estate agent” is “(chiefly US) a person in the business of selling land and buildings.”  

As someone who just bought a house and has spent a lot of time with a realtor this year, this factoid blew my mind. 

Did anyone else know about this? For anyone living outside the US, what do they call people who sell land in your country?