Yes, but the difference was that Obama was not a reprehensible man who openly praised and courted authoritarians and dictators around the world, nor who has repeatedly talked about elections being "rigged" or that he had 2 years of his term "stolen" from him, that the media was all "fake" or "the enemy of the people," etc. I don't think it is at all far-fetched to worry that Trump would do one or all of the following:
- try to influence the election outcome in unfair ways (e.g. putting ICE agents around all polling places to scare immigrants away from voting; trying to change the day of the election; creating a crisis or distraction on election day to make it harder to vote; spreading misinformation about the election; etc.)
- denounce the result of the election as illegitimate if he loses ("it was rigged", "the vote counts were altered", "voter fraud", etc.)
- formally challenge the election result (via a lawsuit, refusing to concede, executive orders, etc.)
- claiming that it is not fair for him to leave office until said lawsuit/challenge is settled
- letting said challenge drag out for months and months, all the while remaining in office
- using the secret service, US Army, ICE, or other armed forces to try to remain in the White House by force rather than exit office
I do *not* think it is a crazy conspiracy theory to be worried about any of these things. Trump has used the military for purposes they are not supposed to be used for, such as manning the border. He has turned ICE into his own personal gestapo. He has fired all the heads of the Secret Service and replaced them with his own goons. I'm not saying he is 100% going to do the above things, just that we should at least think about the possibility and prepare for how we might deal with it if the worst happens.