It was confirmed in some earlier issue that Betty was fired for the Kraven thing; I think she had some early pictures of Miles as Spidey and brought them to Jameson, which is where it came up. It might have been even earlier than that, though...maybe even as far back as the Lafuente UCSM era, or maybe even the Immonen days. I would check, but half of my USM stuff is lent out at the moment. The Kraven thing has been mentioned a couple times though, so it probably is that.
The other stuff is likely, as you suggest, a means to show that Betty was a pretty poor reporter all around. Remember, the Bugle used to be little better than a tabloid, and Jameson himself was pretty radically different at the start (he might be the character that experiences the most growth over the series, now that I think about it), so I imagine that her **** used to fly just fine. It might have been cool to see her call him out on that, but I think it's fine as an implication and I like that a crappy paper attracted some crappy reporters alongside its Urichs.
The other stuff is likely, as you suggest, a means to show that Betty was a pretty poor reporter all around. Remember, the Bugle used to be little better than a tabloid, and Jameson himself was pretty radically different at the start (he might be the character that experiences the most growth over the series, now that I think about it), so I imagine that her **** used to fly just fine. It might have been cool to see her call him out on that, but I think it's fine as an implication and I like that a crappy paper attracted some crappy reporters alongside its Urichs.