At the end of Episode II: when Yoda was fighting Count Dooku, couldn't Master Yoda use the Force to pull out Anakin and Obi-Wan instead of trying to prevent the tower from falling over the unconscious Anakin and Obi-Wan? Failing to do so, Dooku escaped during Yoda's attempt to save them.
AFAIK, there's no in-universe canon answer. The movie of course doesn't supply one.
Neither does the R.A. Salvatore's novelization, really:
“The battle is far from over!” Dooku stubbornly argued. “This is just the beginning!” Reaching into the Force, he took hold of one of the huge cranes within the hangar and threw it down at Obi-Wan and Anakin.
“Anakin!” Obi-Wan cried. He grabbed at the plummeting crane with the Force, and Anakin, startled awake, did so, as well. Even working together, they hadn’t the strength left to stop its crushing descent.
But Yoda did.
Yoda grabbed the crane and held it fast, but in doing so, he had to release Dooku. The Count wasted no time, sprinting away, leaping up the ramp to his sail ship. As Yoda began to move the fallen crane harmlessly aside, the sail ship’s engine roared to life, and all three Jedi watched helplessly as Count Dooku blasted away.
We can take a couple of guesses though:
They didn't know where the crane would land. Simply moving Anakin wouldn't have necessarily helped
It's a basic precept of emergency/trauma medicine, that moving an injured person - especially with the significant amount of force needed to quickly yank someone from under the falling crane - may significantly worsen them.
Even leaving that aside, a Force Push could injure a person in general, if it was done too hard/fast. Human body is fragile.
On Yoda's part, he already had Obi-Wan concentrating on moving the column. So he was better off joining that effort rather than doing his own with unpredictable results and interplay of the Force pushes in 2 different directions.
"Size matters not". For Yoda, lifting the crane may have been just as easy weight-wise as to lift a human.
Now that we said all of guessing, the real reason is one that is always explicitly stated in Star Wars material for actions of a Jedi in battle - Yoda wasn't thinking logically or making considered decisions. He was following the flow and the will of the Force.