The law allows Congress to object, not the vice-president. And Congress was in the process of debating the Arizona objection when all this stuff broke out. Pence did his job by recognizing the objection and adjourning the Senate and the House to their respective chambers.
Pence is not saying that electoral college slates can't be rejected, he's saying he's not the one who can do it.
NOT GOOD ENOUGH! Pence needs to do it.... JUST BECAUSE!!!!