LIGHT 26-121LRa-la If Ra-la acquires a rule that prevents it from being dulled by an opponents Summons or abilities, the replacement effect where the damage you take is reduced to zero and Ra-la is dulled is still applied to it
They don't copy whether that creature was tapped or untapped, whether it had any counters on it, whether it had any Auras and/or Equipment attached to it, or any non-copy effects that changed its power, toughness, types, color, and so on
It's the same reason bribery and agreeing to randomly determine the outcome of an official match are strictly forbidden
While black can turn your life into resources, as previously established, a very common way for black life gain to get to the finish line is by turning your life gain into burn
If on the other hand Buccaboo is removed from the field before its auto-ability resolves, it cant be put into the Break Zone and therefore cannot make your opponent discard 2 cards