grammar - Is a comma required between an independent clause and a dependent clause connected by a conjunction?

Many publications use a comma between an independent clause and a dependent clause connected by a conjunction.

Recent example I came across:

I have to say I roll my eyes at the various attempts to explain President Trump’s decision to recognize Jerusalem as the capital of the Jewish state**, and to make plans** to move the U.S. embassy there.

(Source: http://nymag.com/daily/intelligencer/2017/12/andrew-sullivan-let-him-have-his-cake.html)

This Purdue article seems to caution against such use: https://owl.english.purdue.edu/owl/resource/607/02/

Are these commas grammatically correct? Why do many publications place/allow commas in these instances? Your input would be greatly appreciated!