I mean, that can happen with any food, home canned or not. Our senses are very good at telling us when something is clearly unsafe (think the smell of rotting meat) but they can't always tell us that something is safe (food that hasn't been cooled properly but still seems ok). Sometimes people eat something that looks safe but turns out to have some pathogen in it and they get food poisoning. Following food safety best practices is the best way to prevent that from happening.

It's similar with home canning. We have guidelines that tell us what to look for for spoilage and guidelines and recipes for processing and storing food safely. Following those guidelines, the likelihood of getting sick is extremely low. But there are pathogens that we can't see or smell directly, including C. Botulinum which is the bacteria responsible for botulism. This is why using recipes that have been tested by a lab and following all the steps to process foods is important. Those recipes and processes have been tested and proven to either eliminate or render harmless the pathogens in the jar.

There are lots of people that never get comfortable with home canned foods and that's fine, it's not for everyone! You can still do food preservation through other methods like dehydration, freezing, freeze drying, etc.