We need a cooler head here folks. It is one thing to have a disagreement about how to care for a fish but quite another to jump down each other's throats. Please try to keep things civil on this thread. We all have opinions but there is no reason to get so worked up.
I got curious and did some research myself, I don't keep gouramis, and found that they can tolerate a low temperature at values between 68F and 72F depending on what source you believe. In a warm home, that would be about what I would expect an unheated tank to go to. That means that some people might actually be able to keep a gourami unheated, depending on how warm they keep their home. It would never work at my house but that does not mean it would never be able to work. I would not think a 10 gallon was big enough for a gourami for the long term because they are rather large fish. It is one of the reasons that I don't keep them. I like small fish as my personal preference.