Remember that Trump did not show at the Seder in the White House, though they had one. It is interesting that the Trump excuse is to point to his Saudi Arabia trip.
This is fascinating as they really seem to have - maybe alone - bought their own frame for the beginning of Trump's trip, where - per the Trump spokespeople - he engaged the three great Abrahamic relations in their "homes". Ignoring that many Christians see themselves as very different than Catholics, that Netanyahu is really not a spiritual leader of Judaism, and while the Saud royal family sees themselves as the protectors of Mecca, they are more the political than the religious leaders. In reality, this was a not a trip to honor spiritual traditions of the Abrahamic faith.
In Saudi Arabia, Trump led a large group of Sunni government leaders and seemed to do two main things -- make a deal to sell Saudi Arabia US weapons and to verbally lead a fight against Iran. Neither of these have much to do with Islam and I doubt he learned much about it. In Israel, he simply muddled everyone's view of what his positions are on every issue, while arguing that he was the best one to make the ultimate deal. His trip to both of these countries was political - and it should have been. The third piece, the meeting with Pope Francis COULD have continued the relationship that existed where the Vatican's diplomats worked with us on issues of agreement -- if there are any with the Trump agenda.
There was a very diplomatic article written by Shaun Casey, who led the Office of Religion and global affairs under Kerry. Without hammering the point, Casey describes how Trump's preparation on religious issues were three one pagers, one on each event. https://www.washingtonpost.com/posteverything/wp/2017/05/24/i-counseled-john-kerry-on-religious-affairs-trump-has-no-idea-what-hes-doing/?utm_term=.657eaf4dede9 The article was written before the meeting with Pope Francis. He had a nice description on the little know US and Vatican record of working together on issues where we were of the same opinion.
It is sad that an almost 20 year tradition probably both showed honor to Islam and likely taught many top diplomats something about Islam will not happen this year. Ironically, the top diplomat might need that experience more than any past diplomat. However, its function of demonstrating respect for Islam is likely not one that could succeed anyway - as a ceremonial meal can not wipe out two high profile attempts designed to keep Muslims out of the country - in addition to Trump's own despicable comments during the election.