It's in reference to recent issues the Canonical Snap Store has had with letting malware get past the review process. Since Snaps are pretty tightly integrated in Ubuntu, people with concerns about the Snap store wouldn't want to take the risk with a distro that makes it hard to opt out of an app store with a proprietary backend that seems to have issues with letting malicious apps onto the platform. This matters more to some people than others, but I think it's fair to question Ubuntu's safety given the track record.
It's in reference to recent issues the Canonical Snap Store has had with letting malware get past the review process. Since Snaps are pretty tightly integrated in Ubuntu, people with concerns about the Snap store wouldn't want to take the risk with a distro that makes it hard to opt out of an app store with a proprietary backend that seems to have issues with letting malicious apps onto the platform. This matters more to some people than others, but I think it's fair to question Ubuntu's safety given the track record.