Economists are only doing their due diligence by sending a cautious warning of the Trump Presidency, and they are very justified in doing so. At this stage and with severe consequences of unforeseen actions of a Trump Presidency, it is only the most effective way for our economy to not suffer greatly. If the markets are very optimistically cautious in their actions, it will only serve the public well and possibly reduce any collateral damage that a Trump Presidency could cause. Because we're in uncharted territory, it is only smart for them to warn us and we should take heed. It is not sour grapes, it is simple mathematics.
No, warnings that economists make about a Trump presidency is not due to sour grapes. These warnings are given based on the educated predictions of people who are professionals who have decided to make economics their field. These people are in the business of providing unbiased opinions to the public.
Economists have been saying all along that Trump's economic plan or lack thereof will be a disaster for the U.S. economy. His supporters do not seem to hear this or care. Early reports show his tax plan will increase taxes on single parents and larger families making $50,000 a year. One good way to stifle economic growth is by increasing taxes on the middle class.
Economic concerns of Trump's presidency have merit. He is a business man who by his own admission knows the ways to work the system of business dealings and states that you should never spend your own money on business dealings. These practices may work in the business world but when applied to local and global politics they may get the United States in a lot of financial trouble.