Telengard
Arcane
You're skipping a few steps. Early post-Baldur's Gate Bioware games all had romanceables, but those romances remained still relatively in the background (even as they became more developed), not to mention having few romanceables available. And then along came a thing called Jade Empire, with its hedonistic bi romanceable character, emphasis on the hedonism. That character garnered Bioware a lot of news, and a whole new following.Minor flaw in this would be relating the number of posts on fringe forums with customerbase potential and (relative) size of that group.
You would hope that a overwhelming majority of your customers just play the game, be entertained (or not) and thats it.
Focussing on adressing the needs of a (hopefully) small but extremely vocal group of slightly unbalanced people for whom your game is not just a cheap piece of entertainment, but a life's mission / policor crusade just doesnt seem very smart, marketing wise.
Then they followed that game up with a "bi" alien. And they took a little media heat for that - the only gay romances in 2 games being female/female (saucy), and this time the gay romance character was alien (which means not necessarily a "gay" romance). But even then, Bioware was still only at 3 romanceables in the game.
But now, see, they've got a following in the LGBT community. They've taken some heat for having only straight or female bi relationships. So, now along comes Dragon Age with its inclusion of equal opportunity bis. That's only one more romanceable, which doesn't much change the focus of development, and it satisfies the media. Only, as a side effect, it gets them serious LGBT fans. Plus, with the expansion and development of romance, they're starting to garner interest from romance novel enthusiasts.
Now, throw in EA's voracious need to expand markets. And, it's something that looks simple enough on the surface (as Taxalot said). -Throw in a couple extra romanceables, and please a whole new demographic, thus gaining a bunch of new sales. Romances are a relatively small amount of work, but garner a huge following, a following - by the way - that posts about them endlessly (free advertising).
Couple that with EA's later need to clean up its image, and its use of its LGBT-friendly poster childs (the Sims and Bioware) to help it do so. It's really not so hard to see that aspect not just being emphasized in PR clean-up work and game advertising, but also in executive "recommendations" for game content.
Swirl all that together, and it spits out the Harem Romance Games that are modern Bioware.