There are so many designs for 'longbows' today that the term no longer has much meaning as a good descriptor.
It seems contradictory to call a heavy recurve- risered bow a longbow just because the string doesn't touch the limb when the bow is strung, yet many do. And then there are the hybrid bows...light risers sculpted to mimic the locator grip style of recurves, with reflex/deflex limbs (some mild, some severe) built to mimic the castability of a recurve...also usually called longbows.
You have ASL style (Hill style) longbows, English style longbows, primitive style and myriads of 'stuff' in between. They're all called longbows, I guess mostly to spare us the inconvenience of accurately defining their differences. And just maybe because they let us cheat (a little or alot) when bragging about shooting prowess with our 'longbows', as if there's no differences or limitations at all in how each substyle within the style shoots and physically performs.
So I guess the reason why folks shoot them would be as varied as the subdesigns. I think old-school thinkers more often lean towards the English style/ASL style bows. The learning curve to reach the same skill level is generally longer/harder with them, and some never do achieve their desired level or tire of the added challenges of trying to get there. That's ok. But some tend to blame the bow for their shooting difficulties or discomforts, as if the style itself is inferior and the cause of their inabilities/disdain, lol.
I think those who warm up to old school longbow styles also tend to lean more towards old school arrows...usually wood. Same reason...for more nostalgia and challenge. And probably in good part because the urge to shoot competitively isn't that important to them.
There's no telling why anyone loves or hates the bows they try. All I know is that when I see someone shooting old style longbows and arrows BECAUSE of the added challenges rather than in spite of them, I tend to tip my hat.