I'll preface this by stating that this is probably not a popular opinion.
Notwithstanding the ideals behind the Stolpersteine, they are not exclusively a positive influence. The problem lies in one of the defining characteristics of this project: the stones are placed in front of the houses where the Jewish victims who got deported and executed lived.
This means that if you happen to live in a house tenanted by these unfortuna victims in the past (or even in a new house built where their house was), you can end up with a whole bunch of names permanently staring at you whenever you leave the house. Some, perhaps most, people can ignore that, but for some this constant reminder of pointless death and hardship is quite a burden and can significantly affect their quality of life — should they feel guilty for living? If you speak up about this, you are branded a clueless NIMBY resident or even an anti-Semite (there have been a few of such cases in the Netherlands).
Normally, memorials and remembrances are limited in their influence on people's daily life. Memorials are not just placed haphazardly, but with proper consideration of the needs and wants of those who life in the area, as well as the victims and their descendants. A respectful, serene corner of a public park for example. Events where the victims of past conflicts are remembered are limited in time: you can participate or ignore it, and then move on with your life. Stolpersteine however, just get put there in the pavement whether you like it or not.
Should people be confronted with the horrors of past conflicts? Absolutely — during education and in locations where this is to be expected and one can open up to consider the actions and consequences of the past — but not everywhere, not constantly, and not exclusively (there are, after all, quite a few horrific things in our recent past, certainly not limited to the fate of deported Jews in the Second World War). Unavoidable, the dead commemorated by Stolpersteine stake out quite a claim on the land of the living. I do find that Stolpersteine presume too much upon the public space to the point of becoming tasteless and an affront.