Ils trouvent étrange que je choisisse

Question

I am not sure why the subjunctive is used here.  I understand that trouver takes indicative in the affirmative, but subjunctive if negative.  Here it is affirmative, so presumably the word étrange is causing the change in tense.  Perhaps because étrange has a negative connotation, or perhaps simply because it is an adjective, as in être étrange que ..

Answer

i. I.

‘ Trouver étrange que ‘ behaves grammatically in the same way as ‘ trouver bizarre que ‘, ‘ trouver normal que ‘ and ‘ trouver juste que ‘ etc - requires the subjunctive.

https://www.lawlessfrench.com/subjunctivisor/trouver/

Answer

I think it's the adjective that makes the difference; trouver que just states that you think something is true, adding an adjective expresses a subjective opinion about it.