Learning any new language is difficult, especially for older kids and adults, and English comes with enough pitfalls to make it hard even for native speakers. From grammar requirements that always seem to have an exception to non-phonetic spellings, English is a beast that requires years of study and practice to tame.
You know who didn't care about spelling? Those who developed English language rules over the years. Numerous words don't look at all like they sound: Why doesn't through sound like rough, for example?