[lbo-talk] "tool" as insult?

[123hop at comcast.net]

I keep meaning to ask, why is being a "tool" a bad thing? 

I mean, tools are good things. 

It seems that the implication is that the "tool" is stupid. Or is it that it's being manipulated by someone? 

Anybody know where it all comes from? 

Thanks, 

Joanna