Several social media companies were ordered by a New York state judge to face four lawsuits seeking to hold them responsible for helping enable the avowed white supremacist who killed 10 Black people in 2022 at a Buffalo, New York grocery store.

Justice Paula Feroleto of the Erie County Supreme Court ruled Monday that the more than 40 plaintiffs could try to prove that Meta Platforms' Facebook and Instagram, Reddit, Google's YouTube and other platforms were designed to addict and radicalize users like the shooter, Payton Gendron.

The plaintiffs included relatives or representatives of people who died in Gendron's racially motivated mass shooting at Tops Friendly Markets on May 14, 2022, as well as store employees and customers who witnessed it. Gendron was 18 at the time.

In seeking dismissals, Meta, Reddit, YouTube and other defendants said they merely hosted third-party content and were not liable under a federal law governing such content, Section 230 of the Communications Decency Act, or the U.S. Constitution's First Amendment.

But the judge said the plaintiffs could try to prove that the defendants owned them a duty because their platforms were defective and led to injuries.

She also said the mental distress that many witnesses suffered from the "horrific" attack was a "special circumstance" justifying the pursuit of negligence-based claims.

In a statement, Reddit said hate and violence "have no place" on its platform. It also said it constantly evaluates means to remove such content, and will continue reviewing communities to ensure they are upholding its rules.

The decision's timing appeared unrelated to Reddit's initial public offering, which is expected this week.

YouTube spokesperson Jose Castaneda said that the platform disagreed with Feroleto's decision and will appeal.

YouTube had "deepest sympathies" for attack victims and their families, and tries to find and remove extremist conduct while also working with law enforcement, he said.

Meta and its lawyers did not immediately respond to requests for comment.

The lawsuits seek unspecified civil damages.

"We must hold accountable every single bad actor that prepared and equipped the shooter to target and kill members of Buffalo's Black community," said Eric Tirschwell, executive director of the gun control advocacy group Everytown Law, which filed two of the lawsuits.

Other defendants in the lawsuits include Alphabet, Google, Snap, retailers that allegedly sold firearm equipment and body armor to Gendron, and Gendron's parents.

Gendron pleaded guilty to charges including murder and terrorism motivated by hate, and was sentenced in February 2023 to life in prison without parole.

He also faces federal charges, and the U.S. Department of Justice said in January it plans to seek the death penalty.