I agree with your in laws.
Why are you only doing something in return for something. Isn't this festive period of the year about giving and sharing?
Don't be a scrooge, cards aren't expensive!
I bought a box of 100 cards for $1 after Xmas one year, I send them out each year, and still have some left over for next year. You can't tell me that giving someone a card is really that expensive or that much of a hassle to you. It's the gesture.

This is all about doing the right thing by what you think.
My kid received birthday presents but some people who we had said, don’t bring a gift to be polite literally didn’t while all the others did. When those kids bdays come up, you think I’m going to their birthdays with or without gifts? Absolutely I’ll be taking a gift. A few $ on a small present I would never go empty handed and I’m not teaching my kids you pick and choose where u take gifts. In reference to cards, I personally can’t be bothered with them. Xmas cards; where people choose to send them I read them, leave them up for a week or two and throw them out. They’re not my thing but it’s personal. I don’t mind receiving them but just because I receive cards I don’t send back as it’s not my thing. I find them entirely different to taking a gift somewhere.

Cards are bullshit

I give with no expectation of receiving. It works out well that way. I prefer to buy my own stuff anyway. When I do get a gift I am very appreciative but i actually get a lot of happiness of giving.

If the other person has the same opinion as you, then neither of you will get anything, as you'll both be waiting to get something first 🤷‍♀️ If you want to give something, give it with no expectations.

I dont do cards and as a family unit we decided to only buy gifts for the children

It’s not about being the bigger person. It’s about giving a gift because you care about a person in some way and wish to show it. It should never be about what you get in return or how it makes you look to others.