The very first commandment was, "be fruitful and multiply", to the husband and wife couple God had created.

Paul may have said something differently, but he was talking to specific situations and specific people. Most people don't fit those criteria. Most people who say "it's not for everyone" are still dating, just not getting married.

Stop sinning, make marriage great again!

This is why I wrote "How to prepare yourself for marriage" with my husband! Because marriage is great! And I/we want to help people know how to pick someone they'll actually enjoy being married to, and how to go about finding such a person!