These two statements contradict each other. Either your vote matters (second paragraph), or it doesn't (first paragraph). There is no, "your vote doesn't matter, but a vote for candidate C increases the chance A will prevail." It's one or the other.
Yeah your vote for President in NYS affects the tally for each of the candidates but at the end of the day it is highly unlikely that anyone other than the Dem will prevail. Any vote not for the next runner up only serves to increase the margin that the Dem will prevail by. JMHO.