Re: "prediction". Maybe he thinks this is a guessing game. (When someone guesses correctly, the game ends.) If so, hoping to end the game ...

1. He thinks I'm so stupid that my saying anything about grammar, etc. is like my predicting tomorrow's weather.

2. In his native or favorite language, a word like "prediction" is fitting for some reason.

3. He thinks i made an error when presenting my speculations. Where a (more) correct English would have been "If this were/was correct", I wrote "If this is correct". This (supposedly erroneous tense-shift in the future direction) makes each of my speculation a "prediction" in his mind.

3r. This supposed-error is esp. amusing to him because in his mind this is characteristic of English written by persons of my supposed-race, ethnicity, national-origin.

(testing how replying to msg works)

"co-relativization" -- curious . . . but . . . Now, I'm afraid of saying anything ... I'd get insulted about my "understanding problem" and might get humiliated in public ... with ample references to my supposed- race, ethnicity, national-origin. ....

http://chat.stackexchange.com/transcript/message/3880359#3880359
(testing how replying to msg works)
Did it not work ?