First of all, the stat doesn't mean much. I think the most important stat on this defense is the turnover count... that's where the purpose of the defense is.
Landry getting these tackles is pretty big, because they're utilizing him correctly, and he's getting up in the box and making plays. As far as the linebackers... It doesn't really matter. It probably means that the opposing team offense is running more plays, and therefore we have more opportunities to get tackles.
It's not a good stat.
At any rate, as long as we're forcing turnovers... this defense can give up 2 gillion yards, and we're still going to win games.