Yes, it can be legitimate to block someone for off-wiki
activities.
Our
tradition has been to try to mostly avoid it as being
overly intrusive
into the lives of editors, but it really depends on the context and
complex judgment calls. That's what the ArbCom is for. It is a
depressing and difficult job.
--Jimbo
I do not consider arbcom decisions that diverge much from existing
policies as legitimate. The [[Wikipedia:No Personal Attack]] policy
states that off-Wikipedia behavior is a side-issue. If you do not agree
with that policy then please try to change it. Arbcom decision that
diverge much form existing policies are unfair and erode the moral
authority that the arbcom now has.
Andries