That's an odd comment to me. Different TLDs have different pricing, different restrictions, and so on. Giving the topic some thought isn't stupid. And .com is a pretty crowded namespace.
Country code TLDs (ccTLDs) [1] often have rules set by the country of origin. These rules vary widely, but some of them include country of residency requirements (you can't buy as a foreigner), ban on pornography, or strict adherence to religious requirements.
Popular domain hack ccTLD .ly is required to adhere to Libyan and Islamic/Sharia Law [2]
(edit because my posting is rate limited: )
There are plenty of non-ccTLDs, though, including thousands of gTLDs.
You can register a .horse domain if you want, and as far as I know, there are no restrictions on use.
.com is the cheapest
>different restrictions
.com has the fewest
Anything else?