More people bought 1958 Edsels than 1958 Volkswagen Beetles too, that doesn't make the Edsel a better car than the Beetle. Popularity is not the same thing as value.
Emotion is totally irrelevant here. I don't "hate" Firefox OS, nor do I "like" Firefox OS.
It's just a tool, so I give it an objective, unemotional analysis. That analysis shows that it lacks the features and functionality that are needed for it to be a useful tool for the vast, vast majority of users.
Most people use a phone for practical reasons, not ideological ones. They don't care how "open" it may be if it doesn't run the apps they need or want to use. Firefox OS will have no chance of succeeding in the long run as long as it continues to provide a sub-par user experience.