No one controls you just because you identify as a submissive, not unless you want them too... there is a subtle difference between a submissive/slave in a BDSM relationship and real life slaves or the domestic slaves of the pre-feminist days and that difference is consent. As Oz says, you make the choice. You decide to submit and, at any point in the relationship, you are free to walk away and there is nothing which can be done legally to stop you.

The sort of Dom who thinks that they control ALL submissives and can ask them to send them pictures and the like is deluded and, quite often, a stalker or troll rather than a true dominant. A true dominant knows that you need to build a relationship with a submissive first, get to know them and develop a level of trust before you even consider taking the step into committing to any play.

As Oz says, the conflict between feminism and BDSM is a common one and perfectly understandable if you examine only the surface of the lifestyle as it seems as if the BDSM attitude to women is centuries out of date. However, from what I have seen of M/f relationships (mainly from the outside as I prefer F/m ) there is far more respect and love between partners than there often is in modern vanilla relationships.