Ear infections, why does it happen?

Not good hey!
I have had both of my ears operated on due to surfig and diving, the cold from the waters down south more so caused if for me.
The skin is so thin over the bone in our outer ears that the cold gets into the bone and the reaction is bone growing on bone eventually causing on going swimmers ear.
Any one that drives with the window open during the colder months or in cold climates has some of this going on, with our road rules, the right ear suffers, normally it doesn't get to bad for them, they need something else to go wrong to find this out.
I had both my ears close up for 3 days due to infections in both ears at once, then in go the antibacterial wicks, not good!
Then 2 weeks all up of being deaf. Had to hear through my skull, as we all do to a degree, for weeks. Mine at times would come from letting water in during showering it got so bad, but the worst was from the ocean, that caused mine in the first place!
The water gets trapped by the bone growth and the pores open up and the bacteria and bacteria from plankton that dies in there and off goes an infection. Relied on "aqua ear" for years to keep me going!
I have used my PPE work ear plugs for surfing since the mid 80s and a hood when diving all year round since ten as well.
The ops were gross, one in the early 80s, the next in the late 80s.
The ear is cut off and only some flesh still attaching it with a huge risk of a permanently droopy face from the op damaging nerves, then the bone drilled out, then stitched back on.
Many folks are born with mild swimmers ear and not from surfing and diving damage, they get ear infections off and on all their lives, normally from pools or showering.  https://academic.oup.com/qjmed/article/109/11/759/2631754