It's allowed to be like that because the status quo is hard to change, simple as that. ^^; There have been attempts to 'simplify' English spelling AND the English alphabet, but they never caught on because people are more or less fine with the system we have, apparently. It may be a nightmare, but it's our nightmare~
What weirds me out about some of these complaints is that they're not all the fault of English itself...or rather, they make perfect sense when you consider that English is made up of several different languages.
You find two words with conflicting pronunciation rules? Chances are they have different etymological roots.
You find a word that seems to have its own special pronunciation that isn't apparent at all in the spelling? Chances are it would be if we had kept the accent marks from its native language (some French- and German-sourced words end up like this...we drop diacritics because we don't like them, without realizing that it robs people of a fighting chance when they try to sound out the word).
I think it's all hilarious, tbh~. English is like a big patchwork quilt...some of the pieces are sewn together, and some of them are kind of duct-taped on, and they all come from different fabrics. Maybe it's not very comfortable, but it's definitely interesting to look at. ^^