Humans may not have actively "tampered with the entire global cannabis genepool," but they surely have contaiminated it! I don't think this is "a matter of opinion" at all. With access to the right testing, such as whole genome sequencing, genetic contamination by human-bred plants would likely be detectable and quantifiable. Perhaps, a way to test this would be to compare the genetic makeup of current "true wild landraces" growing wild in the same location (e.g., an Afgan valley) to samples from centuries or even just decades ago.
I would presume over many centuries (or just recent decades) that human cultivation has affected/contaminated the entire worldwide gene pool. Over time, wherever cannabis can grow, some humans have surely been growing it. Plus, pollen carried by the wind can travel long distances. The "true wild landrace" plants growing out there in nature have surely been contaminated by human-grown (presumably selected for traits/phenotypes) pollen over time.
We can agree to disagree.