That stuff is justified, but of course you're clueless about it. The Republican Party has won big five times in the last 32 years. In 1980, 1984 and 1988 at the presidential level, and in 1994 and 2010 at the congressional level. Each time it was because the party was led by the conservative movement (1988 was merely a third term for Reagan, which quickly ended once Bush 41 botched it, which led to Ross Perot). Bush 41, Bob Dole and John McCain's losses, and Bush 43's narrow victories (and loss of Congress) were all products of the "establishment", moderate/progressive, inside-the-beltway, left-over Hoover-ite crowd.
The Democrats have put up a long string of left wing candidates and lost. They put up one moderate (Clinton) and won (barely), and then they won in 2008 with a leftist who pretended to be a moderate, who benefited from Clinton's shadow and now needs it again to rescue his campaign. The Republicans have put up a long string of moderates who have had limited success and massive failure. The few times they've run on a genuinely conservative message, they've won big. You would think at some point they'd catch on.
The point of the statements you quoted is that the Republican Party establishment, as an organization, is a failure because it
should be winning in a landslide. And that message is coming from conservatives, not moderates and independents. The conflict between the "Tea Party" and the Republican establishment is something that I would not expect you to understand or comprehend, and obviously you don't.
I don't know exactly how to characterize this particular point of view coming from white left-wingers. The picture that emerges is of the minority of whites who hold left wing views creating an army of non-whites to get rid of all the non-leftist white people. If you use racial resentment and eliminationist rhetoric to get rid of people who look like you, what exactly makes you think you'll be spared? Eventually (and that point has possibly arrived), whites will begin to disappear from the leadership and elected representation of the Democratic Party. The flip side is that whites will increasingly vote the way minority groups vote, more and more overwhelmingly for the Republicans (another phenomenon that is starting to materialize). That's enough to prevent the victory people like you are predicting in the short run.
In the long run, the flaw in the "getting rid of white people" formula for Democrat victory is that almost all of the "non-white" population increase the left is counting on are Hispanics, and over half of all Hispanics in the U.S. are white. Keeping white Hispanics from assimilating into the broader white population the way every immigrant group has in the past is an impossible task. So while Hispanics are growing as a percentage of the population, the Democrats' advantage with Hispanic voters is virtually guaranteed to be a short term phenomenon.
The U.S. population is 72.4% white according to the
census. 16.3% are Hispanic or Latino. 53% of Hispanics or Latinos are white. Some of the wilder projections of recent years to show whites dipping below 50% of the population rely on an indefinite continuation of peak immigration levels (which have already dramatically declined), and treat all Hispanics as non-white, regardless of the fact that half of Hispanics seem to be under the impression that they are. In other words, it's not going to happen. And remember that George W. Bush already got over 40% of the Hispanic vote. At most, the white share of the population will decline from 3/4 to 2/3. Meaning that those pesky, evil white people will be around (and voting) for a long time to come. Having a major problem with a group that is the overwhelming majority of the population is a lot more electorally dangerous than having a problem with a minority group. If the Democrats aren't very careful (and you might want to consider the wisdom of your own rhetoric here), their open hostility to white people could doom them rather than securing a permanent majority for them.
You may not realize how widely known and understood your "hahaha, we're going to get rid of white people and rule forever" fantasy is becoming. You should think about what it really means for the Democrats if the average voter catches on to it (and they are catching on). To put it for you in numbers, there are increasingly estimates that show the Democrats' share of the white vote dipping below 40%. That means the Republicans' advantage among whites (by far the largest population group, and an even larger share of those who actually vote) is reaching the same level as the Democrats' advantage among Hispanics.
It is tragic that the Democrats are pursuing that kind of openly racist electoral strategy, which will result in parties that are race-based rather than idea-based. But if they succeed in creating that kind of environment, they will lose in the process.
*Neither of those statements is true. The population is not urbanizing, and there are not more progressives (unless you mean an increase in the use of the word "progressive" as a label, which has recently become a popular replacement for "liberal"). The number of people calling themselves "conservative" has grown quite dramatically, and the most population growth is in suburbs, not cities.