Deb,
Britt certainly offers us a very good plausible explanation.
After endless weeks at sea staring at the horizon, the passengers would experience quite the stress upon arrival. No doubt they, like most immigrants not familiar with English, would tend to say yes to any questions in order to appear agreeable, accepting, and cooperative.
So if a few Swedes in a large group of Germans were being processed, and the Germans were getting through without a hitch, the Swedes would likely reply with the same answers.
I admit this is speculation on my part.
Some other thoughts:
Perhaps the Swedes had left their country under difficult legal circumstances and found it ever so convenient to submerse themselves amongst the Germans when the opportunity arose on a long voyage.
Perhaps the Swedes when they left Goteborg, sailed to a German port, from whence they were tallied and listed with Germans heading for the England and the ports with ships to America.
When arriving in England, they could have been listed as Germans in transit. And upon eventual arrival at Castle Garden, it may have been easily said that they all originated in Germany. Especially so if the passenger manifest drawn up at Liverpool, and presented at Castle Garden, already indicated, Germany.
It would be fabulous to find and peruse that passenger manifest !
Thomas