I feel really sorry that they lose all the hard work and I do hope SE gives him a 2nd chance.
But lets be honest, what are bannable actions and what are not has always been very very clear.
They never say X add on nor Y add on being the exception of the rule, nor "being helpful in the community" makes you the exception of the rule. I'm more shocked at people's reactions here than him getting banned, lol.
In his particular case, it's not a matter of "oh I got banned" it's more of "well *** i've been doing this for YEARS and NOW you finally ban me"
SE never say "If we didn't ban this before, it's an okay thing to do". They can be late on banning, see 2008 salvage ban.
Their policy has never changed. It's people making assumptions on what's okay and what's not.