(dons hard at)
in my experience yes it is, but i only know about 30 mums if that. the 5 sets of parents that we spend time with (all have dc similar age to DD) are all bfers - it is one of the factors we have bonded over (that and blw/attachement parenting and other similar parenting choices). we are all very middle class (stating fact, not being snobby).
in theory, the middle classes are by nature more educated and more likely to make informed choices in their parenting. by informed i mean they research it in books/net/consult professional before making a decision.
i did a bf peer supporter course and met quite a few self defining working class mums but most had mentioned that they felt isolated in their bf choice within familes/communities of ff.
but these are sweeping generalisations. bf probably is a middle class choice, on average. but thats a big shame