The difference is that in Washington's case you are still losing if you do kick the PAT. It is much easier to justify what they did than what Philly did. You're ahead by 8 already. You're fine. Just take the 2 possession lead and kick the PAT.
But I still wouldn't have attempted either PAT personally, and I also don't agree, they're not equivalent situations. It's 14-12 in the second quarter, you're losing, I don't think you need to be worried yet about playing catch-up. It's not the same circumstance as padding a lead you already have. You're playing from a clear advantage in the second situation and it makes complete sense to pad the lead.
I suppose just a matter of preference.