Maisy. Don’t be silly, of course every employee has to consider the feasibility of getting to work as part of their decision on where to live 
Clearly a significant number of teachers would need to not to go to work for a school to close. The point is whether every single one of them genuinely couldn’t get in or whether some of them took the easy option and decided a snow day was a better idea (like the teacher who lives in my village).
It only takes a few teachers taking that decision, on top of those who genuinely couldn’t get to work, for a school to close. Perhaps if some of them had made the effort to get in when they could, some of the hundreds of schools that closed might not have done.
Ultimately of course, it’s their right to make that choice. It’s also the right of someone who is personally affected by that decision to be annoyed by it.
The OP’s school clearly said that teachers weren’t at work due to ‘inclement weather’. Not language that would generally be used by pupils making something up and you would assume the school wouldn’t be stupid enough to lie about the real reason if it makes the teachers/ school look worse so the reasonable assumption is that it was true.
With regards to two days of non working affecting results, of course that’s going to be hard to prove either way but schools seem to make a very big deal out of attendance to the point of referring parents for fines for taking their DC out of school so you would expect every day does count otherwise why all the fuss about fining parents?