Of course there is the concept of 'unwanted sexual attention' for a sub. Whoever said there wasn't doesn't understand the concept of BDSM relationships at all. They are instead following an unobtainable (and illegal) concept of sexual slavery where a sub has to accept anything that is dished out to them regardless of their own desires or safety.
The people in the street are not playing a kinky game or engaging in the lifestyle. They are morons who do not understand how a woman's mind works and think that shouting obscentities to her will somehow make her want to sleep with them. This is despite many years of evidence from research by dedicated building site personnel to the contrary. It has also been shown that driving past and shouting something which is barely heard because of the speed you are driving is also not a good chat up technique.
Even a 24/7 slave is not expected to enjoy or participate in this activity simply because they are a 24/7 slave. They are the property of their Master who, it could be said, may require them to participate in this sort of thing but it is not an automatic assumption. Plus there are many subs who are not sexually motivated - what about all the service submissives? Sub does not equal 'easy lay'.