No. Change it to think badly.
But the president is not alone in thinking badly of the developing world.
badly (Adv) – in a defective, insufficient way
esteem (N) – favorable opinion or judgment; respect or regard; estimation or valuation
poorly (Adv) – inadequately, insufficiently, unfavorably
poor (Adj) – inadequate, insufficient, unfavorable
poorly (Adj) – unwell, She is looking poorly (informal); low opinion, She thinks poorly of them (standard usage).
regard (N) – thought, concern, respect, estimation
regard (V) –to look upon or think of with a particular feeling; respect or concern for
poorly. Merriam-Webster's Dictionary of English Usage. 1989.
poorly. Fowler's Modern English Usage. By H. W. Fowler, revised by R. W Burchfield. Oxford UP, 1996.
"Third World Countries Map." By Roke~commonswiki, Wikimedia, 14 Jan. 2006. Licensed by CC BY-SA 3.0. wikimedia.org/wiki/File:Third_world_countries_map_world_2.PNG
Gay, Roxane. "No One Is Coming to Save Us from Trump's Racism." NYTimes, 12 Jan. 2018. nytimes.com/2018/01/12/opinion/trump-shithole-countries-haiti-el-salvador-african-countries-immigration-racism.html