Q:

What's an adjective for someone who is quick to comment on a situation but unwilling (or unable) to commit to providing a helpful answer?

It seems to me that many people exhibit this tendency and I am looking for a good word to describe them.  They love providing feedback but in a passive-aggressive way.  They love giving their two cents but stop short of actually putting themselves in the position of having to commit to an answer. 
For example, I might write the following sentence:

On the English Language & Usage stack exchange, certain ________ people are more ready to populate the comment section than they are to provide answers. 

A:

This reminds me of the difference between "involved" and "committed" being like ham and eggs (the chicken is involved, the pig is committed).  
"Uncommitted" sort of works, but maybe uninvested is better, as in not invested in participation.  It's a usage based on one of the definitions of "invest": to involve or engage especially emotionally - M-W

