One possible answer is the Prison Industrial Complex. According to OpenSecrets, Hunt Companies, Inc. was the top individual contributor to McConnell's campaign from 2017-2022. In 2012, Hunt Companies acquired CGL Companies, one of the largest architecture and planning firms for private prisons in the United States. CGL has essentially verticalized the prison industry, with its own architects, contractors, and financing for the construction of new prison facilities. Eli Gage, CEO of CGL, was quoted as saying, "The rising popularity of private prisons, coupled with a projected 0.5 percent annual increase in national incarceration rates, will boost the industry overall."
This conflict of interest could explain why McConnell is so opposed to cannabis reform. In 2020, McConnell was the fourth-highest recipient of donations from the for-profit prison industry. In total, his campaign has raised over $75 million from corporate America, including tobacco and pharma companies. Despite publicly stating that corporate CEOs should "stay out of politics" and "don't pick sides in these big fights," McConnell has a long history of allowing money to influence his politics.
In conclusion, it appears that McConnell's opposition to cannabis reform, including the SAFE Banking Act, may be influenced by his connections to the Prison Industrial Complex and other corporate donors.
The ONLY way to remove his opposition is to VOTE HIM OUT!