I would go out on a limb and say the negative connotations are correct in most cases and usages. E.g.

"I'm just going to hack something together." (usually means do substandard work but with the benefit of speed)

"It works, but it's a nasty hack." (a workaround that might be clever, but isn't necessarily safe, testable, or repeatable).

A "hacker" in the sense that GP is using it means somebody who's default method of working involves doing the above on a regular basis.