Why is προσκυνέω translated as "worship" only when applied to God but not when applied to men?

I have noticed a consistent bias in English translations of the scriptures, both old and new. Whenever the Greek προσκυνέω or the Hebrew וַיִּשְׁתַּ֖חוּ appear (in their various conjugations), if the word is applied to God proper or to "a god," then the word is translated as "worship." However, if the term is applied to your average man then it is translated as the more literal and mundane "to bow down, to prostrate oneself." A great example of this is Exodus 18:7 (NASB) >Then Moses went out to meet his father-in-law, and he bowed down and kissed him; and they asked each other about their welfare, and went into the tent. If you review the Hebrew, the word translated here as "bowed down" is וַיִּשְׁתַּ֙חוּ֙. And if we look at the Greek of this verse in the Septuagint, the word is προσεκύνησεν, the 3rd person singular aorist active indicative conjugation of the aforementioned προσκυνέω. But when these words are applied to God, we see they are translated as "worship." For example, 1 Samuel 15:31 (NASB) >So Samuel went back following Saul, and Saul worshiped the Lord. The Hebrew word here is again וַיִּשְׁתַּ֥חוּ, while the Greek from the Septuagint is again προσεκύνησεν; the exact same as for when Moses "bowed down" to Jethro. As far as I can tell, this distinction is entirely artificial and has been abused by translators to falsely build up the case for the Trinity by selectively translating the Greek word as "worship" when applied to Christ, just as when it is applied to God proper or to "a god," and not translating it in the same manner as when applied to men. For example... Matthew 28:16-17 >**16** But the eleven disciples proceeded to Galilee, to the mountain which Jesus had designated to them. **17** And when they saw Him, they worshiped Him; but some were doubtful. The Greek word translated as "they worshiped" is, of course, προσεκύνησαν. This is nearly identical to the word used when Moses "bowed down" to Jethro - only it is 3rd person plural instead of 3rd person singular. On to my question... While it appears to me that the above practice is an abuse by translators to force their biases upon the unsuspecting reader, I want to know if there is in fact a good, objective reason for this practice. Any references you can provide to substantiate your answer would be much appreciated.