Reformed Christians are more plentiful than they used to be, but we have not taken the forum by storm.
1. As LaurenTM pointed out, a great deal of the threads related to Calvinist soteriology are not started by soteriological Calvinists. They are, by my observation, started by those who maintain a different theological point of view and usually do not open it up to a different point of view. Weeks ago, I stopped seriously debating the topic here because all people do is cry heretic and let slip the dogs of bore.
2. The fact that "Hyper-Grace" "Free-Grace" and "Radical Grace" are being coined tells me there are not enough Reformed Christians here. None of these terms have gained common coinage in our theological circles to the best of my knowledge. In churches I've been to across the country, these terms have never been used. Now "Hyper-Calvinism" and "Free Grace" but they are both castigated as aberrant sub-circles or heresies. The point is, the terminology the OP uses and the terminology mentioned in the sticky is not Reformed Theology.
3. Subjects Reformed Christians love to debate- Baptism, the Regulative Principle of Worship, Church Governance, Theonomy, the scope of Christian Liberty, and Covenant theology are rarely debated head on or given a thread dedicated to them. If there were a giant portion of us on this cite, these internascent squabbles would be more palpable (and interesting). As of now, they exist in jokes on the Miscellaneous subforum.
Again, we're more plentiful than we ever have been on this site and it seems logical me because we are a growing segment of Christianity in America and when Calvinism is debated and Calvinist scholars are discussed, "Spurgeon Discussion" will lead them here. This is taken from an actual anecdote told to me over PM.
And as somebody who has been here for years, seeing a few other people of my theological persuasion on this site has been an unexpected joy (Merry Christmas). But if Hyper-Grace, Radical-Grace, and Free-Grace have gained common coinage, either the site is actually being besieged by heretics, my brothers are not giving a very good account of their theology, or they are being purposefully mislabeled by the likes of the OP who lay in stark theological opposition.
Soli Deo Gloria