Josh Seiter says he didn't correct the fake death post about him for a full 18 hours because his priority was figuring out who hacked into his Instagram account ... it's all very puzzling.
The ex-'Bachelorette' star appeared on "TMZ Live" Wednesday and we peppered him with questions about the long, long period of radio silence ... both from him and his family.
Josh says he was trying to manage a ton of texts and calls from concerned friends/family, which raises the question ... why didn't someone he called tell media outlets -- including TMZ -- the death post was a hoax?
Fact is ... we called Josh just after the death announcement was posted, but didn't get a call back until the next day. We also called family members, and they either hung up or said "no comment."
He recognizes he's going to get scrutinized, but he says he handled it the best way he knew how and is standing firm -- he was hacked.
Josh says he's a victim in all of this and makes no apologies.