It seems exceedingly likely that this is so and that the small number of hospitalized individuals merely means that the absolute risk is very low either way whereas the risk of the vaccination is lower yet and the optimal strategy to minimize risk to yourself and more importantly to others is to vaccinate.
This is from 1-dose - I couldn't find the supplementary data for that study on 2dose/3dose
but needless to say that no this study does not in any shape or form suggest that it's exceedingly likely that a young no-comorbidity person is more likely to get severe disease with 2dose vs 3dose.
edit: found the data for 2/3 dose comparison - which again does not support the claim, because this is not age stratified data - and we know covid had significant age preference
