1) Since 5e, the lore also has been adjusted and Drow were elevated from KOS status to viewed with suspicion status. It is possible to have a Drow in Baldur's Gate.
2) Drow character was not necessarily picked up there.
3) They probably did not want to slap penalties on the race and tadpole is convenient loophole there that can be a valid explanation.
Nope, drow having some level of social acceptance above ground goes back to the early-90s. That's also when the guidebook to the drow came out and introduced Eilistrae, Vhaerun, and the like. 3.X is where they started getting playable PC stats (though they had ECL...so "playable" is more appropriate). The 00s is when you also started getting computer games with drow as a playable option (NWN2) or character (Demon Stone)....though, Zhai in Demon Stone is again more likely to be statted as a wood elf (her father is a wood elf at least, and she was raised among wood elves rather than drow).
Saying this change happened with 5e is just flat not true. In the real world, drow have had established surface presence and non-Lloth sworn communities for decades....in Faerun it's been at least 800 years and probably closer to 1000.
Drizzt first appeared in 1988, Qilue first appeared in 1995. Liriel Baenre first appeared in 1995 (I originally posted 2003, but I had a re-release copy for comparison, felt wrong as I remember reading it high school, so double checked and yep, mid-90s). Eilistraee and Vhaeraun were introduced in 1991. And both Eilistraee and Vhaeraun at the time were established as being primarily concerned with the surface (Vhaeraun is actually considered the god of dealing with the surface among drow.)
So 2nd edition AD&D is when non-Lloth sworn drow were being established and when significant surface settlements were established as a thing.
