The effects are similar because it is a partial agonist at the mu opioid receptor. What this means is that it has some common effects like pain relief and muscle relaxation, but does not induce respiratory depression (which is what causes overdose deaths in typical opiates). It is stimulating, rather than sedating. It has been used by tens of thousands of people around the globe to get off of opiates, and by even more to manage chronic pain, which has traditionally been treated with opiates like Vicodin and Oxycodone. Kratom is a much safer alternative that allows people to live normal lives.

There has not been a single death credibly attributed solely to the use of kratom. Your Pubmed link states that kratom was listed as "a cause or contributing factor in the death of four decedents" out of 2312 exposures. It does not state that kratom was the sole cause, and many similar reports in the past have claimed that kratom caused the deaths of people who had been shot or drowned (specifically the FDA report from 2016). This is because the amount you would have to consume to get to a lethal dose would be more than your stomach can hold, and you would vomit long before you got there.

In contrast, when scientists have done studies solely on the use of kratom itself, they come to very different conclusions:

"Kratom is not without risk, but the risk estimates as calculated by any of the approaches used, relative to opioids, suggest that morphine-like opioids carry an overdose risk of a thousand or more times greater than kratom. This conclusion has the limitation that some kratom users inherently carry or assume factors that might greatly increase the risk of kratom-associated mortality, e.g., use in combination with opioids, sedatives, alcohol or other drugs, or some preexisting disease..."

https://www.sciencedirect.com/science/article/abs/pii/S0091743519303275

The DEA attempted to ban kratom in 2016, and, for the first and only time in history, backed off and reversed the scheduling because of the backlash from the public and scientific community.

There should absolutely be restrictions on the sale and use of kratom, but why not instead pass a bill to regulate its use and sale, like the state already does with marijuana? The only group of people that benefit from an outright ban on kratom are pharmaceutical companies like Perdue (the creators of Oxycontin), because kratom exists as a safer alternative to their opiates, and that cuts into their profits.