Society had no issues with this for the past millenia. This new social construct of adulthood and finding it weird is far more recent. Mohammed’s first wife was 41 when he was 25. Age differences at the time were far more usual.
Granted that our culture now changes so fast that it would mean someone that grew up with Madonna and someone that grows up with Skibidi toilet would get together. The generational cultural gaps are far greater than in the past. But this is overcome when people spend time together.
The only real reason that people can use is that a younger person can be easier to manipulate. Which holds an element of truth but the question remains at what age we allow a person full control over their actions. Currently this is 18. Yet research suggests the brain is only fully matured at 25. So will the new age be 25?
The Leonardo DiCaprio example is a classic one. Most people that say they would never act similar to Dicaprio will do so once they are actually presented with the option. It is moral highgrounding purely based on never having been presented with the option.