Comments at the end of a line bad style, why?

[zachariah]

My robots.txt validates, but has "bad style". I thought it is common practice to allow and use comments either on lines by themselves, or after code on a line, in all computer languages. Just looking for reasoning that makes this "bad" style. I could easily move it up to the line preceding, but I'm just curious why it matters. What problems does it cause to do it this way?

warning
Comments were detected after a valid field name. Although ok, this is bad style.

User-agent: * # all robots are to use the same rules at this site!

[DaveAtIFG]

The protocol [webdoc.gwdg.de] permits comments, just as you've used them. You're using an overzealous validator. :)

[Krapulator]

I remember reading somewhere that some badly written bots stumble on these when they come across them (even though it is perfectly valid to have them like this).

Better to be safe than sorry!