Let your firewall do its job, as it is doing. You don't want to let anything in that you don't know exactly what it is. I typically get 1200 to 1700 of those per day that are blocked.
It looks like a WBS IP which is why my initial thought was why not. But as jmn says if things are still working with it blocked then I'll just leave the status quo.
its another user just like you, when you have spyware that spreads or zombie bots on your system they scan IPs in the same range as you so just because another user is on your ISP it doesn't mean you should allow traffic from them.