What I am thinking of is not exactly like the Lazy argument described in Wikipedia. I am thinking of a general argument where a normative conclusion towards inaction is drawn from the knowledge of the extreme improbability or certainty that the goal of that action cannot be achieved. For example, "it is extremely improbable or almost certain that you will not be accepted into Harvard, therefore you shouldn't apply"(assuming that person is dull). Another example could be an "active" argument, such as "it is extremely unlikely that you will be attacked by a shark in Maine, therefore it is safe to swim". These type of arguments are obviously "valid" or sound (I don't know what the correct word to use would be), and I think also the person who would defer from those normative conclusions would maybe even be considered irrational.
In contrast to these, there seem to be "invalid" lazy arguments where the normative conclusion seems wrong or bizarre, for example "you shouldn't bother eating healthy, since death is inevitable" or "science is pointless, since absolute knowledge is impossible" or "you shouldn't bother preserving the species, since humans will eventually go extinct".
So My question is, why do the more practical arguments of this type have force, but the later ones seem sophistical? I was thinking maybe that the first type of arguments have actual achievable "goals" where those of the second type seem there is some sort of equivocation or confusion about what the goal is.