On Reddit, the woman was described as a "trifecta of ageist, sexist and racist".
"Exactly what does a traditional white family look like? Please explain more," one person commented.
Many pointed out white people are not under-represented in toys or figurines, while others explained why she couldn't find a family of dolls resembling her own.
"This particular case is a non issue. They have previously stocked what she's asking for but they sold out, and because of Covid supply chain issues they can't get any more," a Reddit user wrote.
"How do I know this? Because I respectfully asked Kmart instead of complaining on social media. The kids wanted dolls that look like our own family. What's wrong with that?"
"I get what they are after, but good God, they could hardly have phrased that any worse," someone else said.
"Imagine going to buy some toys and not being able to find one that represents your particular family. Such a struggle being a white hetero," another person wrote.
One Reddit offered a practical solution: "Buy both the same-sex sets and exchange one partner. Problem solved (which is probably why they did this, kill 2 birds with one stone, be diverse and encourage people to buy more)."
Kmart has previously made headlines for the diversity of its toys range, which includes different types of families, as well as dolls representing people with disabilities.