Comanche = "Enemy"?

I'm curious about the etymology of the ethnonym Comanche and I'm wondering if anyone here can help me. I'm aware of the conventional etymology given, which is that it comes from the Ute word kɨmantsi, which is said to mean either "enemy", "enemy, foreigner", or something to the effect of "Those who want to fight us all the time".

What I want to know is, are any of these definitions accurate? What are the constituent elements of kɨmantsi? It seems to me that "Those who want to fight us all the time" has five elements to it (they + want to + fight + habitually + us) that would be difficult to fit into a three-syllable word. Some of these could be combined, of course (they acting on us + habitual desire + fight?), but I don't speak Ute so I have no idea how efficient the language can be at conveying information like this. Also, where the heck did foreigner come from?

There's a potential historical snag to these etymologies as well. According to Wikipedia, the first mention of Comanche in writing comes from a Spanish soldier in 1706 in New Mexico who relayed a report that the Utes and Comanche were planning to attack. I wasn't able to find the letter, but I found a different letter written in the same year by the governor of New Mexico who makes an offhanded mention of the Comanche. The Utes and Comanches later had armed conflicts with each other, but that wasn't until the 1730s-'40s. If they were allies in 1706, why would the Utes refer to their allies as "those who want to fight us all the time"? Does this perhaps reflect a much more ambiguous relationship between the two than what the Spanish assumed? Or does kɨmantsi have a wider semantic range than is normally reported?

For reference, the sources that I've found so far are "Native American Placenames of the United States" By William Bright, p. 117, on Google Books, which gives the etymology as from Ute kɨmánci, "enemy, foreigner" and cites "J. McLaughlin, p.c.", whatever that means (all I can find under that name is a clothing store).

And "Historical Documents Relating to New Mexico and Nueva Vizcaya, and the Approaches Thereto, to 1773" compiled by Adolph and Fanny Bandelier, p. 381, on babel.Hathitrust.org, which contains the letter mentioning the Comanche but doesn't have anything to say about them except that they live north of the Navajo, as do the Utes and the "Carlanas".

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