Can anyone explain to me how the American stock market is up for the year after everything that is happening (tariffs)?

Left over momentum from the election. Stocks rose pretty continuously from the election on because businesses expected a "pro-corporate" President. They started correcting a week after Jan. 20th inauguration and his tarriff tantrums began to bear fruit, corpos realized they fucked up. "YTD" being zero or only slightly positive/negative only means the markets have fallen back to where they started pre-Trump.

There is a long, loooooong way to fall still.