First off, please don’t be turned away by the different tones you get on the internet. Not everyone is the same, and especially over the internet, people can sound harsher than they really mean, because it is a sensitive (and important) issue.
I understand that it seems disrespectful but there is a certain reason why the Church does this. It’s not because the people aren’t good people, or decent enough, or anything like that. It has to do with the way the Church sees the role of the godparent, which is perhaps different from the secular or legal ramifications that you may be familiar with.
The Church views baptism as giving grace to a person but it is only the first step - the person must grow in the life of grace. And like any other process, the person needs role models - for a child, the first is obviously the parents, but after the parents, it is the godparents. Role models not simply in a secular way, but primarily in a spiritual way. It is for this reason that the Church asks that one person be Catholic. And ideally (although often people don’t do this and opt for relatives) it should be someone you know who is deeply committed to practicing the Catholic faith - not even someone who just perfunctorily goes to church on Sundays and forgets about God for the other 6 days.
As many other posters have pointed out, the Church takes baptism very seriously. It’s not just about be named, or a type of cultural custom (not to imply that you necessarily understand it in those ways). As any gift, God’s grace given in baptism has to be nurtured and taken care of.
I mean, it’s like if you gave your teenage child the keys to a fancy house. You’d probably expect him/her to take care of it, but if he/she doesn’t, and throws huge parties every second day, the whole place will go to ruin. Or, to use another analogy: a relationship. After you meet someone, exchange contact information, you don’t just go home after the first date, and then call back 4 years later saying “Hey, will you marry me?”. You probably spend some time thinking abt the person, talking to the person, etc., etc. Same with baptismal grace (mind you, the analogy does break down, because if you call God after 15 years, he’s always available!) and this happens in different ways.
One is the example - religious especially,for example in praying regularly showing children that talking to God is necessary and important - that the parents give the child at home. Another is attending Mass every week - not simply because its the culture, or X grandparent will be unhappy, or someone told you you’ll go to hell if you don’t - but because we believe that the Mass is a great sign of love left to us by Christ himself, to enter into communion with God and with our neighbours.
It’s for this reason that you have heard of all these requirements. Some churches ask that you attend regularly so that they can know that you are serious about trying to live a life of faith. Others ask for proof of marriage in a church for the same reason. It isn’t that you aren’t doing good moral things without attending church or being married in a church, but if you believe (as the Church does) that our souls are created by God and find their ultimate joy in a relationship with him, then the life of faith is important. It’s kind of like a plant settling for a leaky irrigation system that gives it the trickles of water, when it could be near the banks of a river and have all the water it needs. (yes, yes, I know I go overboard with these analogy things…


).
Going to Mass weekly, and getting married in a church is a sign that you understand why the Church asks for these things, and why it says that it is important. If for any chance you don’t know, and you’ve never heard of it before, there are people who will be happy to explain it to you. And of course, Google is your best friend after God and saints.

You can even post questions on this forum - just filter out the more …um… strident replies.
(contd.)