No, they either were told the same things or may be assuming it from their care of axolotls, their white ones may have been weaker than their dark ones.
Our first lot of axolotls, the two white ones were weaker than our wildtypes; one even now gets fungus every so often ( i don't put it down to colour type but that she was very possibly a weaker axie to start with, or maybe her sickness compromised her immune system which is why she is susceptible to illness/fungus). Of our older axies, our wildtype is weaker than it's tankmate (leucistic/white) and tends to get sick before the leuc does.