Is the character of Rev. Lovejoy from the Simpsons created to look
like the Rev. Jim Jones who founded the infamous cult of the People's
Temple? The resemblence of the two is freaky.

Interesting theory! Now that you mention it, I do see the resemblance.
But I would think that if they had intentionally modeled Lovejoy after
Jim Jones, there would be occasional Kool-Aid references. And Rev.
Lovejoy is scarcely a cult figure. He seems to be a mainstream fundie.

Matt Groening is definitely known for his political commentary through
tongue-and-cheek humor in the Simpsons. Perhaps he is making a
comparison between cults and mainstream fundamentalism. I feel a
doctoral thesis coming on...