On the question of how the Tensi would not recognise humanoids as sentient lifeforms/sophonts, this has come up in Star Trek before.
In the licensed, non-canon Star Trek: Enterprise - Rise of the Federation novel "A Choice of Futures", the mushroom-headed aliens from the ENT episode "Silent Enemy" performs experiments on other species because they don't recognise them as creatures with feelings.
When I saw "It's Coming Home", it got me to re-read the relevant section:
“Thank you, Admiral. I do not claim that the aliens’ intentions toward us are harmless. In their view, we are an inferior and dangerous form of life. They see us as we would see wild animals.”
“But we’re clearly not that,” th’Menchal objected. “We have language, technology, civilizations.”
“We distinguish persons from animals on those bases, among others. They evidently do not.” Sato leaned forward. “Their senses let them literally see inside each other, sense each other’s reactions and emotions. We call them Mutes, but in reality they’re in constant communication, linked on a deep level. To them, that communication is fundamental to their sense of personhood. It’s intimately linked to their feelings, their thoughts. We don’t have that kind of connection, so to them, it’s like we have no real awareness or emotion.”
Source: Bennett, Christopher L.. Rise of the Federation: A Choice of Futures (Star Trek: Enterprise Book 15) (S.264-265). Pocket Books. Kindle-Version.