I thought this too (and I still kinda do) But I understand the "suspicious" when someone pointed out that it counters what Lotor said to Allura when they were climbing the cliff to get to the temple. He was talking about how he could work with people other than Galra and learn from them without using violence/subjugation. It made him sound like he honestly sought peace as a valid option before violence - like an Altean would.
And while I agree that it was some fucked up spirit/ghost lion that only seconds ago tried to fry the fuck out of your friends/temporary allies and that Lotor had every right to fight it off, he did not even consider that peace could be an option. And then he in fact demanded the lion give us its secrets, when that's not the Altean way (you blend in and live peacefully among others in order to learn from them.).
Furthermore, it's little odd that in all his years of reach about Altean culture and their "ways," that he wouldn't seek that very peaceful solution - especially after having immediately watched Allura give those guardians that magic stone and spoke to them with deference/humility.