Welcome to 2019 where this is "clearly" homophobia. No other possible explanation. Do you have any evidence that they would not say this to a straight couple? I guess neither of us do. So that means the business is guilty. Right?

You can look at the website. They clearly have 2 types of rooms. Those that fit 2 and those that fit 4. They are both the same price, at least from what I checked. Imagine owning a hotel and managing capacity for walk-ins near an airport. Do you think their goal is matching people up to their sleeping capacity, or keeping gay people out of the same bed? This is honestly a ridiculous discussion, and jumping to an extreme conclusion.

I can appreciate that perhaps a better explanation could have been given. I also think you should get the room you booked. None of these things convince me of the homophobia accusation.