Dunno what sort of "calvinism" you refer to here. Had you been read up on it well you'd see that "the calvinism of Calvin" certainly do not entertain any antinomian ideas at all. "Calvinism" has a very different view on the law and its uses than does the arminian OSAS people. They should not be confused. This said, from whatever angle, to divide law and gospel is really the crucial issue here. And, yes, total depravity and human inability (to respond to God's calling or having true faith before regeneration) is also very important.
Now, here's why that doctrine is stupid: Satan is the most depraved being to ever exist, and grows more depraved by the hour, it seems yet he's still fully able to discern the presence of God, communicate with God, debate with God, and exercise free will choice to disobey God in all things where God allows it....
..........but...........
.....humans who are light years behind Satan in depravity -- in our knowledge, thinking, and years of experience -- are somehow so "totally depraved" that we can't discern the presence of God, be approached by God, reasoned with by Him, and then offered a choice by Him to either walk with Him or go the other way, unless we are among the "chosen"?
Calvinism is just another form of "Exclusivity Religion" not unlike Luciferian occultism, Catholicism, Eternal Tormentism, etc., all of which say, "I know the path and you don't because you're not worthy, so away with thee, ye profane."