He even tried to convince to Mike Pence to not signing the recognition of Biden as president.
Yes, and this is a perfectly legal practice. Democrats have done this at least 4 times in the past and the first time in the late 1800's I think, it went through successfully, turned out that there was fraud all over the place, and the republicans ended up winning. No joke.
The most recent time from the democrats was merely 2017!
The other attempts did happen but like this one, didn't go through. Just because it's not common, doesn't mean it's not legal.
What part of the constitution gives to the president the choice of accepting or not the elections after all the process has been done.
That's backwards. What part of the constitution outlaws a president voicing his opinion on a matter? If he was to act upon it and, say, form a militia keeping him housed inside the whitehouse, that would be another story. But just whining and complaining about it is perfectly fine - as long as he leaves on the due date.
That's not a constitutionalist attitude
Key word there: attitude. It's not unconstitutional, but you may find it's not the right 'etiquette' of a president. But when was Trump ever 'presidential' in attitude? He's just some rich guy.
He also passed the constitution by his balls when separated kids from their fathers with all the inmigration policy.
True, and I have no doubt he has almost violated the constitution countless times, but then, so has Obama (a cliche comparison I know). Forbes even wrote a 'Top 10 constitutional violations in 2013' article.
It's not very useful to say that because every president crosses the line from time to time. The severity of that constitutional breach seems to be the key - and the media's attention to it which drives up the emotions of the people and pushes the agenda further.
I don't personally care how much people hate Trump, however, it's my hope that this level of pure skepticism and outrage will continue through the Kamala Harris era, rather than giving her and Biden a free ride simply on the basis that they are 'not Trump' and faux-left wing.