Everything has security issues. That’s a good thing as it means there are people finding things. I do wish Debian was a little faster on patching things but I also understand that they have a limited number of people. There are thousands on packages and a large amount of new security vulnerabilities. Patching takes man power and they only have so much to go around.
Debian isn’t this security mess like this person makes it sound. They can be slow on patches but the reality is a lot of these vulnerabilities aren’t getting readily exploited in the wild. Just keep up with the security tracker and follow basic security practices such as least privilege and security in depth.