Because it's their language and it's not English, they can twist their foreign words into whatever they want.

Same way Americans can't pronounce foreign words properly

Hi! I've seen your replies to various people. Calling Japanese people "illiterate" simply because they can't fully pronounce English words is extremely rude. If you are expecting everyone who is foreign to have perfect English, then I think it's only right for you to be fluent in every language. I'm half Japanese myself, and I've met people are very good at English despite slight accents. Just because they don't pronounce orange "properly" doesn't make them uneducated or dumber. You probably can't pronounce some Japanese words properly either. I suggest you take some language lessons before criticizing others.

Because of how the Japanese phonological system works.

accents. Personally, I have a problem with accents as well, since I’ve grown up bilingual. Sometimes I pronounce German words in Korean accent or Korean words with a German accent.

accents

They are used to a different inflection because they use different vowels so the tongue movement can be difficult i think

Accents I assume, idk I’m not Japanese