FYI, from my understanding this is an extremely common behavior for most op-ed boards ex adding a headline when none was sent in, or editing the submission itself for length/formatting/etc. Most groups will require you sign something allowing them to review and publish the letter and may request sources or your own connections to the topic to identify and disclose a conflict of interest. This generally makes op-eds more reliable gauge of public opinion and viewpoints vs a blog style opinion article bashing an industry rival.

Some groups like NYT have retired the term 'Op-Ed' name in favor of something like Guest Essays as it better conveys the intention of the submission: https://www.nytimes.com/2021/04/26/opinion/nyt-opinion-oped-...

It's also important to note that local papers may print what is provided vs editing for spelling/grammar or even fact checking a submission. Larger publishers who by simply printing it add weight to the original may exercise a higher degree of involvement. For a look at the NYT process when you submit a piece: https://www.nytimes.com/2013/10/14/opinion/op-ed-and-you.htm...

Anecdotal, but every letter I remember I or my family wrote to the local paper was edited in some fashion, most often for length. Short articles were the least touched, if at all, as they had the least content to make fit on a page of newsprint. I think it's also near impossible to get a non-partisan source either simply because that term is applied to basic human decency these days like how it's apparently partisan to wear a mask.