I guess the two terms can't be mutually exclusive, though.
A point was brought up in the chat room today about imagining if it's possible for two bromancees to be so comfortable with each other that, if opportunities arose, that they could jack off. In fact, I think it would be easier to do something like that just because the comfort zone is generally better expanded between these two men. If anything further, anecdotally, a man might prefer not to "waste" the boner and if his buddy is riled up too, they could fire away.
(I'm trying not to make it sound as fantastical as two guys jerking off together in an amateur porn type sense. I want to emphasize the impact of expanded comfort zones.)
It might be a harder case to rid the excluisivity the other way around. Bromancees might be comfortable enough to pursue physical interaction, but it's a bit harder to plead the corresponding relationship (e.g. emotional impact for those in a man crush). See below.
Two dudes mancrushing on each other might be perpetually caught in a admiration-hesistance realm of interaction. The idea of jacking off with his friend might be very captivating and promising indeed, and he might even recognize some attraction he has toward his friend. However, for fear of being crushed, rejection, spurned, or made vulnerable by his admiration for his friend, he keeps very quiet as to not disturb the blissful-enough dynamic as is. Unlike the bromancees, the mancrushers haven't developed enough interpersonal intimacy. They certainly might demonstrate some of it (even unknowingly), but the intimacy there is always externally directed to some sort of activity -- drinking together, playing sports together. Beyond admiration and superficial knowledge, say, of one's tolerance for alcohol or athleticism, the mancrushers hardly know much about each other beyond surface.
Emotional contact does happen, but it isn't to the same degree of commitment as evidenced by bromancees. To be sure, bromancees are probably well aware and self-aware of their feelings and thoughts while participating in a broad range of interactive behavior. They know their care and esteem and love for the other person; they feel comfortable, enjoy the time and the comfort. When traversing into physical or sexual interaction, they are thoughtful enough to stay as self-aware regardless of the level of contact.
(This is to further specify that bromancees can exhibit a wide range of physical behavior so long as they both feel it's consensual and safe. There is no certain way to determine if the two would jack off or do more than that, but it would be done in a cognizant manner.)
Whew. Enough intellectualism for now.