I get tons of emails from recruiters, marketers, etc. I reply to none of them, and I think it's unfair that by sending me mail that I don't want they are implicitly entitled to labor (writing a response) from me.
I don't think anyone was suggesting that you should reply to them. The complaints are about people who are unresponsive to direct questions from their co-workers that require timely responses (at least that's how I interpreted it).
