Just because someone applies to a company they don't automatically become fanboys and lose their right to complain, especially on Pprune of all places on the internet.
If they pool together +50 pilots that meet all the prerequisites, took time off and traveled at their own expense to the assessment the least I'd expect is a little bit of information.
Why not give information regarding offers, course dates, scheduling, benefits, intake numbers? You seem to forget that assessment or interview is as much an opportunity for the candidate to sell themselves as it is for the company to do the same.
As for complaining about not typing in Spanish, the name of this thread is Vueling 2019 a company which does Not require Spanish. At no point in the assessment did they present bilingual slides let alone even speak in Spanish.
Perhaps this would be better suited in interviews board because Vueling, once again, is not a Spanish speaking company anymore.