There are no other electrons to collide, repel and kick Hydrogen's single electron to a distant nucleus. And that a single electron is tightly attracted to the nucleus by the electrostatic energy between them. So it seems to me, that Hydrogen does not require ionization energy at all.
But when I checked on the sources - the Hydrogen's ionization energy is relatively high.
Even Hydrogen makes $NaH$, which just doesn't stay for long and has extreme need for becoming $Na$ metal and Hydrogen gas.
So in this case why can't we say that Hydrogen does not require ionization energy?