Felgrand the Divine Dragon Knight TCG ruling?

alright so ive just recently got back into yugioh and been playing on ygopro, while in a tag team match my opponent played felgrand, my team member played torrential tribute and it targeted itself and avoided being destroyed and did it again next turn with dark hole. now i've looked all over and there is not official TCG ruling for this card anywhere, but Felgrand's effect is this;

"Once per turn, during either player's turn: You can detach 1 Xyz Material from this card, then target 1 face-up monster on the field; this turn, its effects are negated, but it is unaffected by other card effects."

now is it so much to ask for this effect to just be what it says it is!? it should not be able to target itself simple because the cards own effect negates the effect of what ever monster it targets???

so this card can target itself as some unwritten broken rule but yet my beelze can be destroyed by solemn warning when his effect is says he cant be destroyed by effects or battle and his doesnt say "while this card is face up on the field" it says it cant be destroyed. should it matter where its at if felgrand gets to be broken for unwritten reasons why not other cards????