Why is there a “temple” for him? 

Why is Abraham Lincoln so beloved? 

I visited the Lincoln memorial, discussed with a great American specialist of Lincoln and modern history and made 3 conclusions:
1 Person – embodies the American Dream and story. From rags to riches, never give up, sacrifice, get things done, humour, God…

2 Timing. Happened to be the president at the crossroads of U.S. history (civil war). Compare Washington too. Or Jefferson (not).

3 Need. America needed shining “holy” figures to memorize – Lincoln the best choice in 1914-22. (Afterwards no equivalents…)