Honest, I have literally never heard anyone ever say "junta" with a hard /j/ sound. Is this really a thing?
I have heard too many people say "jally pea no", but the most frequent pronunciation of jalepeño is with a hard j
Spanish itself is full of loanwords, particularly from Arabic, which are not pronounced like in Arabic either (which Arabic, anyway?)
There is no better or worse, there are just words that travel across languages.