Is it permissible to feed and host the Sufis during their annual celebration of the deceased, knowing that they invoke him besides Allah and commit other innovations?

Supplicating the dead and asking of them, besides Allah, the Almighty, is major shirk (polytheism). Whoever does this must be denounced and advised, with the reality of their action explained to them, rather than being aided or affirmed in their shirk. Aiding in disobedience to Allah is a sin, so what about aiding in disbelief and shirk? Providing food at innovated (bid'ah) occasions is objectionable, so what about occasions involving shirk? Some scholars have explicitly stated the impermissibility of spending on the establishment of mawlids (celebrations of the Prophet's birthday) because they are innovations; so what about spending on occasions that involve shirk?