I would say this is not a problem, and in many cases those few extra applications may avert a big disappointment.
Congratulations if you or your kid get into the dream college, affordable, with just 6 apps submitted. Seems about half of kids submit 6 or fewer.
But to many kids who may be unsure of their ideal college environment, or needing merit, or on the cusp of acceptance at several dream schools, then 10-13 apps might be appropriate. And with the Common App and many schools not requiring supplemental essays, the extra apps are not extremely burdensome. Moreover, some kid sending in a lot of apps is really not hurting you or your kid’s chances at their target schools.
So relax and let each family apply as they see fit for their situation.