Please note that the headline of that article says, “Explosive device found at Planned Parenthood”, while the story specifies that the device actually exploded.
“Found” and “Blew up” are two totally different things.
“Found” means that it was discovered and did NOT blow up.
Also please note that this is probably not going to be reported as a terrorist act. Just another bomb at another Planned Parenthood. Nothing to see here. Move along.