This GiveWell blog post by Holden Karnofsky is critical of donation matching, for the same reason that you mention:
We’ve discussed whether we might be able to provide “true” donation matching – finding a donor who would give to our top charities only on condition that others did – but not surprisingly, everyone we could think of who would be open to making a large gift to our top charities would be open to this whether or not we could match them up with smaller donors. Ultimately, the only match we can offer is illusory matching.
This GiveWell blog post by Holden Karnofsky is critical of donation matching, for the same reason that you mention: