I believe that lean/six sigma is simply boiled down engineering thought processes for non-engineers. I have witnessed too many times an uninformed black belt kaizen something, think they have the whole solution without the technical training to fully understand the scope, run to management with the "answer" and have no concept of the engineering ethics that have been violated.
Six Sigma is just a lot of meaningless mumbo-jumbo. I’m surprised more people haven’t figured this out yet.
It sounds like you have had some disappointing experiences, but no it would not be fair to assume that everyone practicing lean six-sigma is not technical or that lean six-sigma is just techo-babble for non-engineers.
I am a Lean Six-Sigma Black Belt myself, and a professional Engineer with thirty years experience in the Aerospace and Defence industry. I can assure you that there is nothing inherently unethical about Lean, or Six-Sigma.
If a Kaizen is properly executed, the Black Belt acts as a facilitator, and the Kaizen team is a multidisciplinary team drawn from the groups who are engaged in the work under study. Lean Manufacturing and Six Sigma each approach the question of how a business can improve the performance of its processes.
Six Sigma aims to reduce or eliminate variance in a process, so that it produces no more than 3.54 defects per million opportunities. Lean Manufacturing aims to reduce or eliminate waste. Lean Six-Sigma combines the two concepts, applying them in that order, on the premise that there is little point to eliminating variance in a process that should itself be modified or eliminated.
If you think a Black Belt has manipulated a Kaizen team or event to legitimize some proposal of their own, instead of helping that team to come to its own conclusions, based on the facts and using the specialized tools, then you should ask that Black Belt to walk you through the Kaizen work products so that you can understand how the Kaizen came to those conclusions. Look for a Value Stream Map or a Process Flow diagram, some analysis of how far product is travelling, how long it is waiting between process steps, how much inventory is backlogged, whether product is exiting the process at a regular pace that meets the customer’s takt time. If you find none of these things, it was not a Lean Six Sigma Kaizen. If you do find those things, and understand how they were used, you should end up by feeling better about what happened.
Good luck.