Yes, it is subjective and you’ll find that Crockford himself doesn’t mind which is used either, as long as it’s consistant.
The issue of tabs vs spaces only becomes a problem when you are coding with other developers, at which point there’s an issue of change control among the code as developers fight like a pack of squabbling cats for control over the code base to set their own personal preference, and waste time converting everything back and forth.
As such, some sort of standard must be set for harmony to return, and it just so happens that the spaces side of the camp is seen to have less potential problems than tabs.
If you just so happen to prefer to indent using tabs, then clearly you will have problems with jslint.