Earlier quoted context omitted.
This is my reason for preferring tabs. Plus changing indent levels is faster via arrow keys.
And even faster using tab or shift+tab to pop up or down a level, regardless of whether you're using tabs or spaces.
I do this too, along with Home/End to navigate. Once in a while though I want to move only half way left of the indent, which is one press on tab, 2-4 of space. Can't use ctrl+left there.
But more than anything I'm sure it's just familiarity.