Why do so many commanders (Battalion or higher) not understand or like combat engineers?

I am in an infantry battalion as the engineer liaison Nco with the guard now. Our battalion had an attached engineer company this last time in the field. The unit had no desire to even try understanding what engineers bring to the battle space. I had company commanders tell me that when they want billets assembled they will ask for engineers, and that we have no place on recon movements, or breaching complex obstacles. Engineers with R2C2, an EOCA are completely discounted by many leaders who would rather wait hours/ days for EOD to show up to even confirm an IED.

I've only had one good experience while attached as a Sapper company in support of a unit and that was my most recent.
Other than that I noticed they, for the most part, really just don't understand how to use us. They don't want to utilize the resources on something they don't fully know how to use.

As a former Engineer Battalion Commander I think I may shed some light on this question. In my experience supporting BN TF and BCTs I believe matter goes all the way down to Company level. Maneuver company 1SGs were not happy cats about having to feed, fuel, arm and water sappers with attached equipment, and there infantrymen do not like to string concertina for their obstacles. I have had one exception. It was during Purple Dragon 98' We supported the opposing forces. It particular there was a 1SG from 1/187 IN. He had to have Company sized "Battle Stars" completed with VFP for TOWs, CSW FPs, and Protective wire obstacles. He was great! he provided sketches of the positions, and a detail to assist with carrying wire and finishing the CSW positions. At the TF level very few staff officers grasp the value for the attached engineer company. It may be due to the dual role that the EN CO. CDR played (TF ENGER/EN CO CDR). Also, because of the volume of engineer specific information in the TF OPORD and the Transport required to more the ENGR CL IV/V. At the Brigade level I found that if the CDR consults and uses the EN BN staff then you as the BDE engineer have accomplished your mission. I also think that when the supporting Engineer Platoon, Co, or BN has success early on in the exercise or deployment then the maneuver folks will value them more, but if you show-up unprepared to work and fight, and not proficient they will treat you like a bad girlfriend! Such is the lot of a Combat Engineer! "Essayons"