If (as an extreme hypothetical) one side used lies and laundered foreign money to win the election, and the other side didn't do that and lost, then the losing side doesn't need to "accept responsibility for their own failures", they need justice.
We don't yet know the full story of what actually happened in the last American presidential campaign, though, so this is moot for now.
Then instead of focusing on accepting responsibility for their own failure, the losing side would need to focus on addressing their lack of ethics and potential criminality. (Both sides would need to focus on that, regardless of whether they won or loss).
Unfortunately I don't know what "justice" would look like in such a situation, but perhaps re-running the process without the unethical and criminal elements would be a good first order approximation.
>But what if, extending your extreme hypothetical, both sides used lies and laundered foreign money?
They both did. But one side is accused of taking money from scary Russia, while the other took money from fluffy bunnies Ireland, England, France, and other allies.
The "us versus them" narrative is easier to work with than the "us versus other people who are allied with us but also not supposed to do these things."
Plus, America has loved underdogs since the days when baseball was interesting. Since H lost, it's usual to attack T. If H won instead of T, then it would be the other way around. It's just how America works.
If (as an extreme hypothetical) one side used lies and laundered foreign money to win the election, and the other side didn't do that and lost, then the losing side doesn't need to "accept responsibility for their own failures", they need justice.
We don't yet know the full story of what actually happened in the last American presidential campaign, though, so this is moot for now.