[optimisticcynic]

Luke A seems a lovely guy, and hopefully that's why he has such support. Lauren would have had similar support. The transgender issue is minor in terms of votes and I don't see why this has to be latched onto to explain his success. As I see it, a good housemate is a good person who is in the house as opposed to someone who has a fake relationship, causes trouble and strife by bitching, or lies and schemes at every opportunity.
I think the difference in votes is reflected within the actual house, where some of the public that may have voted for them were lost due to:

Lauren
1. jealousy and disliking her as a result eg Ashleigh
2. resentment due to previous rebuttals of affection (men identifying with Adam's experience and feeling she is a tease, though I think she wasn't that bad)

Luke
1. Not really done much to be misconstrued or seen as a threat as had not yet bared his teeth as he did with Becky.

Hence Lauren would have lost more potential votes in an eviction where both were hopefully well-liked. As someone else said, like them both and am happy she got a good reception.