I will not reply to you or if I do my response will be neutral. An employee can get in trouble if he is critical of his current employer.
I completely agree. But it's still possible to respond neutrally, truthfully, and informatively. For example, it's possible to just answer with positive aspects and leave out the negatives--that's still valuable info. Or someone can honestly talk about whether the culture is, for example, high-energy or more laid-back -- each has its advantages. Are you saying that it is _not_ at all worth cold-emailing a peer in a p…
In short, +1 to the parent comment. It should definitely be possible to gain useful information from an e-mail that focuses on the positives.