Part of the answer is because of the difference between solids and liquids. In solids, the atoms and molecules are bound together by atomic forces and the atoms stay kind of locked into positions. In liquid, the atoms and molecules still attract each other enough to keep them together as a mass but the mass can move as a body.

Now, Lunar gravity pulls equally the same on solids like dirt and mountains as it does on liquids, but with solids the force is generally not enough to move the solid whereas with fluids, the atoms are free to move around in response to forces. Even the water in a glass of water will move a very very very small amount under the influence of the Moon's pull, but it's very negligible but not really measurable. The Moon actually does move mountains a tiny tiny bit but they really don't flex much at all. The Moon has a very small effect even on tectonic plates but not enough to cause earthquakes. The Moon also even pulls a little on Earth's atmosphere, which bulges just a little bit toward the Moon but not very much.

And by the way, the ocean pulls on the Moon too! The Earth and the Moon each pull on each other.

Oh, and you might ask why doesn't dirt fly up because of the Moon? After all, dirt is loose. The answer is, the lunar G force is actually pretty weak on any small piece of the Earth and not enough to lift dirt up against the Earth's pull. But the Moon's gravity is enough to make the ocean slosh around and in fact get dragged as the Moon rotates around the planet. And that drag is what causes tides to move. Just imagine a gentle but very very big vacuum cleaner sucking on the water and flying past. It will drag the water along.

Part of the answer is because of the difference between solids and liquids. In solids, the atoms and molecules are bound together by atomic forces and the atoms stay kind of locked into positions. In liquid, the atoms and molecules still attract each other enough to keep them together as a mass but the mass can move as a body.

Now, Lunar gravity pulls equally the same on solids like dirt and mountains as it does on liquids, but with solids the force is generally not enough to move the solid whereas with fluids, the atoms are free to move around in response to forces. Even the water in a glass of water will move a very very very small amount under the influence of the Moon's pull, but it's very negligible but not really measurable. The Moon actually does move mountains a tiny tiny bit but they really don't flex much at all. The Moon has a very small effect even on tectonic plates but not enough to cause earthquakes. The Moon also even pulls a little on Earth's atmosphere, which bulges just a little bit toward the Moon but not very much.

And by the way, the ocean pulls on the Moon too! The Earth and the Moon each pull on each other.