JLS were in the bottom two, they went on to finish second and outsell the winner.
Olly Murs was in the bottom two, he went on to finish second and I've no doubt his album will also probably go on to outsell the winner.
Both of them are currently #3 and #2 in the charts respectively at the very moment
Therefore I'm not sure why people think being in the bottom two shows people are hugely or generally unpopular. Obivouisly if it happens more than once (or FOUR times) then alarm bells should starting rining.
But both JLS and Olly proved that you can fall into the bottom two despite huge fanbases, generally when fans get complacent or the act just has a bad week or does something different to what their fans are used to.