Two orders of magnitude is a very large range.
The Moon has a mass of $7.342 \times 10^{22}$ kg, so your question is, why do most dwarf planets have a mass between $10^{20}$ and $10^{24}$ kg?
By definition, a dwarf planet has to be in hydrostatic equilibrium. Considering a list of possible dwarf planets, the smallest/lightest for which there appears to be consensus that it is in hydrostatic equilibrium is 90482 Orcus, with a mass of $(6.348 ± 0.019) \times 10^{20}$ kg. Smaller bodies are too small to reach hydrostatic equilibrium. Hydrostatic equilibrium means that a body becomes spherical. Generally speaking, small solar system bodies are very far from spherical. It is not a requirement for a body to exist at all, but if it's not spherical, it's not considered a minor planet.
The Moon is also in hydrostatic equilibrium, which it would probably not be if it had less than 1% of its actual mass.
Now why are there no dwarf planets larger than $10^{24}$ kg? That exceeds the mass of Mars ($6.4171 \times 10^{23}$ kg) and approaches the mass of Earth ($5.9724 \times 10^{24}$ kg). Such large planets in the inner solar system are full planets and not dwarf planets. Such large bodies in the outer solar system have not been discovered and probably don't exist.
If the moon were two orders of magnitude larger, it would be as heavy as the Earth, and the Earth-Moon system would clearly be a double planet.