Many people have as an immutable axiom "I am a good person"
When you suggest they are doing something bad, like contributing to climate change, this clashes with that axiom.
That clash causes discomfort. Most people are, frankly, lazy cowards. They could accept that they are not being a good person all the time, and update their axiom. But that's scary and feels bad. They could also try to do something about climate change (or whatever the topic is. see also: veganism), but that's also hard. It's far easier to just lash out at the source of discomfort.
The oatmeal did a comic on basically this topic: https://theoatmeal.com/comics/believe
This is the best answer.
The receptionist really doesn't care. You're one of dozens of people they see every day. They're not going to remember or care if you ask for help.