The words of rebbe were “nerein divreihem midivreinu”, their words appear true more than ours”. Rabbeinu tam says that he didn’t agree, but lacked a way of answering them at the moment.
The divrei yoel writes that he couldn’t explain to them the kabalistic channels in shomayim, since you can’t teach that to goyim.
Others say that he was admitting. But the chachmei yisroel had noy darshened a pasuk. Most of the physical statements in chazal are derived from pesukim, carrying the full weight of a deoraysoh drashah. Some are mesoros, like the synodic month.
Even their own conclusions were based on their immersion in learning. They didn’t copy the goyim; we have no reason to think they did when they ruled seforim chitzonim assur.