The short answer answer is, you shouldn't be seeing this.
If 10k+ users notice that a substantial number of a user's answers don't meet our quality standards, a single 'other' flag should be raised to alert us to that. Sure it's possible that you might not notice it until you've flagged a few, but at the point where you scream "holy mother of Zed, we have a problem here!", the next thing to do is raise a single flag to let us know.
In this particular case, I sincerely think that the user was just trying to be helpful. He kept posting links to resources that helped people, and the community kept giving him up-votes and check marks to say thanks. The user received no signal that they were doing anything wrong until everything was brought to light at once.
Even in cases where some sort of malice is clearly intended, flag the stuff you think is serious and let us take it from there.
Now, on to what to do about it. A couple of users noticed the trend and left single flags on some of the flagged answers that basically said:
Something isn't right here. Why are so many posts from this user in front of us? WTF?
At that point, we got involved and contacted the people that needed to be contacted. Raising any valid concern on Meta is of course perfectly acceptable, however flagging guarantees that the right people will see the issue in the shortest amount of time.