There are so many benefits for a front end application (written in javascript) to just assume it will be the backend that does type validation. A new field column added to a table? Cool, update the api layer, but the javascript just gets "the object" and now you have access to it immediately. No need to duplicate your definitions in both code bases, and it's not like front end security is real anyways. Sounds to me like a lot of "I learned to code in some derivative of C" programmers couldn't possibly consider that different languages could be optimized for different use cases and just want all coding to be "what they're used to." Then they moralize it and use shaming language to push it on everyone else. F typescript. I use different languages for different things, and strong typing makes a ton of sense IN MOST INSTANCES, but certainly not all.