John, I think it is stupid, because they should have just made it remove all invulnerable saves and things would have been simple. But GW went and made it confusing like they always do.
But I am pretty certain the way it is worded that Daemons do not have wargear. The description on page 73 of Chaos Daemons says that Daemonic Gifts "are equivalent to the weapons and other wargear used by mere mortals."
It doesn't say "counts as" wargear. In other similar rules disputes, the phrase "counts as" is taken to mean that item A actually is item B and things that affect item B also affect item A. "Counts as Jump Infantry", for instance, means that something is actually jump infantry for all rules purposes (and sometimes infantry or a monstrous creature in addition).
If you want to remove the 2++ for blessing of the blood god, this wording is where you should probably start your argument. You could possibly show that "equivalent to" is just as good as "counts as".
You might be able to convince everyone, but I don't think it's worth the research or the argument because the situation is just so unlikely to ever come up.