Paul wrote much on the subject of being confident in one's faith. Not knowing Paul personally we couldn't be sure, but based upon his writings, one should not have been afraid to attend out of a legalistic concern.
Read the account of Paul in Athens, on Mars Hill (Acts 17:16-34). It argues against what Benke did and said--more specifically, against what Benke failed to do and say.
Paul was "greatly distressed" to see that the city was full of idols (v. 16). Did Benke seem "greatly distressed" over the idolaters who were leading that service with him? On the contrary, he said, "Oh, we're stronger now than we were an hour ago." He called the adherents of the false religions his "sisters and brothers," in a religious context. He invited them to join him in prayer, as though they all were praying to the same God.
In Acts 17, Paul said that the idolaters were wrong about their notions of God and called it "ignorance" (vv. 22-29). Did Benke do that?
Paul said that God now was commanding them to repent (v. 30). Did Benke do that?
Paul said that God has set a day of judgment for the world (v. 31). Did Benke do that?
Paul was sneered at and cut off before he could finish (vv. 32-33). Benke voluntarily finished and didn't say anything that was clear or direct anyway, and he was cheered.
Finally, at Mars Hill, Paul did not lead a prayer service with pagan clerics. Benke did.
But the Rev. Benke did not pray and speak like Elijah. Instead, he prayed and spoke like a pleaser of men, affirming their idolatry and effectively reducing the one true God to one among the pantheon.