The other suit might still have a few deadly snakes without being full of them, and we don't know how many harmless snakes (or anything else) are there.
All of the reasons already mentioned, but also, your brain is hardwired to pay more attention to a face, and to a face expressing emotion even more in particular.
The first two panels establish a pattern that your brain subconsciously keys in on. At a glance even without registering the specific images and text, your brain instantly knows that panel 3 doesn’t fit in the pattern.
Because the other suit is a LOW IQ INDIVIDUAL and a RADICAL FASCIST LEFTIST MARXIST LUNATIC that HATES THIS SPACESHIP! Also, these snakes are actually good for you, everybody says so. The venomous-snakes-in-space-suits economy is booming. Why can't you just be happy for the venomous snakes, you egoistic, self-absorbed ingrate?