Actually if something like that did permanent physical damage, to someone already in that mindset, that could have serious psychological consequences. When was this, has he behaved notably worse since?
It was posted 7 years ago and by then it was said that it was 10 years old, so 17 years ago...that would place this ball-busting incident in 2007, he only became presidont in 2014...idk...maybe it's his origin story (become president to censor the whole internet to hide his 3rd degree ball-trouncing event), like Trump's correspondents' dinner or Orban's being mocked by Juncker or putin's whole life since 1989.
He was prime minister from 2003 to 2014 before initiating a constitutional referendum, creating a presidential system for him in 2014. Ball slapping happened 4 years into his prime minister government.
At the very least if there was physical trauma, the mental trauma from it going untreated could definitely lead to trying to compensate for how he feels about it by "trying to be more manly" to prove it didn't affect him...