In the same way that sports betting on small tournaments has a greater risk (paying a player to do something immoral), politics is no different.
If we take a smaller country and a less important political position, the chances of that person running as a candidate just to manipulate a result are very high.
I like it when we have several betting niches in different segments to choose from, but I believe that bookmakers need to carefully analyze each scenario to minimize the possibility of manipulation.
Manipulation happen even on sports games but the way they do it doesn't look so obvious but politics is a scary one that many people are emotional about. The last time Biden won the US election, some of his fans when to the whitehouse protesting and where climbing walls that were take down by security operations, this tells you how emotional people can be when it comes to elections and hence the reason many gambling platforms don't list political events.
Some Bookmakers can also be politically motivated to do their dirty tricks on people, imagine having Biden and Trump on their website with 48/52% odds on both candidates and after Biden step down, the odd would definitely be favoring Trump than any otter candidates and if they are Trump guys, who knows they can be paid off to increase the odd so people can place their money on Trump and emotionally, people will go to their polling units to vote Trump so that they will have it in mind of winning their bets, so many tricks in political gambling.