Thank you!
My native language has much simpler grammatical structure than English, and it is easy for native English speaker to "spot" it by the diction and word choices even if I manage to be grammatically correct. It can be frustrating at times; but if people still want to protest while reading for free, they might as well edit it for me 
Maybe that is why I tend to be more understanding of hobbyist writing with some grammar mistakes; they are unpaid and therefore often cannot afford an editor (even if there are grammar checkers, humans are better), they also probably don't speak English. That is different when it's professional (whether it's trad pub, self pub, or even premium creators here); you have very little excuses.
One of the loophole I created is to make majority of characters in my series does not speak English or speak different English. Although it is frustrating when people trying to correct it even though it is meant to be incorrect.
Are you a native English speaker by the way?