I think its also about degrees. What constitutes as a rail enthusiast? Nearly a million people visit the NRM every year, but I suspect most of them don't stand at the platform's collecting train pics/numbers. 80% of people who visit preserved railways do not classify themselves as 'enthusiasts', yet, there must be some degree of enthusiasm or interest.
Are you an enthusiast for choosing train travel over say car travel for a specific journey?
Are people who are members of pressure groups, enthusiasts? Take pressure groups. Some people might be interested in supporting rail for social and environmental reasons, but it doesn't mean they are interested in trains themselves.
Do you have to collect numbers or take pictures to be an enthusiast, in which case I am not one? Not all enthusiasts buy books, or collect model railways, for example, or play with rail simulators. Raill enthusiasts do not fit into neat boxes, far from it. Some cannot stand steam and vice versa, for example. Some surprisingly enough, are not actually all that interested in trains themselves. I class myself as a RAILWAY enthusiast, not a TRAIN enthusiast, for example. Meaning, I am more interested than in just trains.
Some people also class themselves as enthusiasts and do not see any reason to ever travel by train.
Generally, I like quite a lot of things, I am enthusiastic about them, but I wouldn't say I'm an enthusiast of them. It's all about inspiration, it might be that elements of certain things inspire males more than females for some reason. But it doesn't mean that there is no crossover, it just means one aspect might predominantly appeal to men.