People who doesn't believe an alien existence are in these 2 cases:
1)Fear them
2)Too much selfesteem.
Um what. Where is your logic in this? Not beliving in something wont stop people from fearing them. People fear many things that do not exists god, satan, ghosts, the boogie man etc.
Any seemingly intelligent and reasonable person should not be against the possibility of aliens. I'm not stating that people who do not accept their existence are stupid, but that people who are relying on math should know that it is highly improbable that we are the only intelligent species out there. This is why that guy is correct. Similar stuff applies to religion, due to the fear of nothingness after death.
Besides, if there are species that are equally intelligent (or more), we would also be aliens to them.
I even fear allot of things i know, and wtf has intelect got to do with being alien lol