Shin Okada said:No. But I asked about this to my friends who are native speakers of English and they said in tihs case your argument is wrong.
Because those dictionary definitions and examples are not covering actual use of the word "lose" in dally conversation or in writings.
They are incorrect.

Daily use of lose in the context of a cohort (or an item) does not mean the same as in "lose your temper". You cannot voluntarily "lose" an object or possesion. You can "give it away" or "dismiss" (in relation to a person or lving creature under your authority) but you can not voluntarily "lose" it.
An example of how "lose" is used when it does not correlate the situation at hand.
You can "lose" your shield, but that basically means that you "unequip" it, not that you can't find it anymore.
You can "lose" a tail but that but that means to have the person following you no longer be able to locate your trail.
Are they native speaker of the US version? I know this sounds silly but there are vast differences in how the same word is used in the US or Britain or even Australia. All speak English, but each has different "slang" and common speach. Not to mention that the US is very conservative in its use of the letter "u" - "color" versus "colour", "armor" versus "armour".