The answer to the first is the stock market loves stability and hates uncertainty and both the Fed and the media have been flooding us with predictions of a dismal future, all of which have failed to materialize. First the Fed raises interest rates and raises fears of inflation, but has since revised this assessment, then the media flooded us with reports the tax reform would increase the deficit, but in fact, federal tax revenues have increased since the reform went into effect, and then the media treated us with predictions we were heading into another recession, but as the economic news continued to be very good, they stopped pushing that prediction and then they predicted that job creation would slow down in December and January, saying it wouldn't even reach the important 200,000 job level, but it exceeded 300,000 jobs both months and these included the highest number of manufacturing jobs since the boom years of the 1990's. How could the media reports have been so consistently wrong? In any case, the media gave the stock market many (false) reasons to worry about the economy, and the stability loving uncertainty hating stock market responded by ignoring the economic news and bracing for the impact of the false reports in the media.
The people that make the decisions that move the market do not have such a superficial view of things, they do not rely on the network news for their decision making.
A few things for you...
Between Jan and Nov (the time frame the tax cut was in place) tax revenue grew by a whopping 0.0015% compared to the year before. We will find out next week if December taxes will keep that small growth or not.
During the same time period in 2017 (Jan - Nov) tax revenue grew by 3.3% compared to the previous year. So, at best the tax cuts cost us 3.2985% growth in tax revenue.
So, while a huge April allowed the predictions of the tax cuts decreasing revenue not to be true, it was by the skin of their teeth. And keep in mind that April is the month all the people that owed taxes from the previous year pay their remaining tax obligation, so April was huge not because of the tax cut but because of 2017 taxes.
When the jobs report came out, the market went up a little bit, but not enough to over come the trade war.
You are right that the stock market loves stability and hates uncertainty, but what is causing the vast majority of the uncertainty is the trade war, not fluff pieces in the MSM