Classic case of 1+1=20 billion.
Soros supports a bunch of different social goals, by giving money to NGOs to hopefully shape policy or events. So do the Koch brothers, famously. And millions of other people to greater or lesser degrees. I certainly do when I donate the ACLU, EFF, NRA, etc.
Donating money to pro mass immigration groups is not being "the architect of the European Migrant Crisis". Firstly, folks have been illegally immigrating to Europe from Africa or the Middle East since about 35,000 BC. That's how people came to get to Europe. There have also been exoduses out of Europe as well. Trying to pin mass migrations on any one person other than a general, emperor or dictator is just plain silly.