If don't fully agree with this. Simply because what you said is not really correct.
First of all, I do agree with the fact that the time is a bit too long, but from the other side, it's not that you have something to reply to every minute. If they decrease the time, 50 seconds will be enough in my opinion.
Also, what you said about the 100+ messages is not really correct. To start of, having 100+ messages doesn't mean that person won't spam. That would be the same like "everyone who has a forums activity of 1 year+ can become a staff member, although it may seem very rude, what I just stated doesn't mean you can trust those people. I don't know if you know this person, but a player called RynezDev had over 5000 messages, and all of the sudden he started hacking and doing things a normal player would never do. So my point is, even if you have 100+ messages, that still doesn't mean that person will never spam. People can change.
+ It's fairly easy to get 100+ messages nowadays.