Lloth specifically blesses her followers with red eyes to mark them as 'hers'.
No, she doesn't. That's the problem.
Drow, as a people and culture have the reputation you describe. Drow. Not the "magically easily identifiable evil drow", just Drow. There are not "Magically easily identifiable good drow with the special magical pass that lets people know they're good" either.
Drow that have abandoned their society and culture and sought a better way do exist. More of them now than ever, in fact. Enough that there exists a minor populace of them on the surface, and there are even drow that have been born and grown up as surface drow, never connected with Lolth or drow society at all. Unfortunately, they're still drow; they still look like drow, and they are still likely to meet people who will want nothing to do with them - or even to kill them - based on that fact alone. They are not a different race or even sub-race. Race has nothing to do with it; they are Drow, and they don't have an in-baked fact of racial physical distinction to prove that they are 'good', or that the other ones are 'bad'.
The whole "This group is a separate race and two separate sub-races, and they have visible physical differences to tell you who is evil and who isn't, based on their race" thing - that's not Wizards. That's Larian. And it's gross.
