"The weather is bad": This one is the least convincing of them all.
Where I live it's 90°F (or higher) with 90%+ humidity at least six months out of the year (more like 9 lately though) and it rains heavily at random in random locations on any given random day. When the weather report says, "50% chance of rain" what it really means is that all day it will be raining down on 50% of the county for ten to twenty minutes at a time (LOL).
The argument that website is making is that if the weather is that bad it's too awful just to go outside (which is 100% accurate haha)... Therefore the weather preventing cycling is a myth? WTF? It's silly.