To my reading the main difference is that the specific issue behind the Elizabeth Warren question is trivial whereas the two Trump question relate to important global and national political issues.
The Warren question has a perfectly reasonable answer, which highlights why it is a poor question.
It is a "big deal" because many people consider it undesirable to have leaders who lie. Lying is generally considered to be morally wrong, and makes government accountability difficult to achieve. Lying frequently about relatively trivial things is considered by many to be an indicator that someone will lie about more significant things later.
This answer is utterly generic and could be pasted into any question about any politician lying about any issue.
The Warren question is about an incident that happened decades ago. One which is routinely 'hidden', in that few workers wish to tell prospective employers they were fired from their previous job. And few employers would care to advertise they routinely sack people for being pregnant no matter how common the practice was at the time.
The first Trump question is about a speech on Holocaust memorial day and why it didn't directly mention the Jewish people. It is not about lying, it was current and well documented and I am struggling to find any point of commonality between the two questions.
The second Trump question is about lying, at least tangentially. If by lying you mean not following up on a promise made on the campaign trail. It is about a recent and indeed ongoing issue where Trump has not followed the US political convention of releasing his tax returns. And then by extension touches on his retention of business interests another convention he has ignored. The answers are all specific to this behaviour and discuss the serious dangers of conflicts of interest inherent in being able to influence your own financial position while President and not releasing the information that would allow the public to see if you had done so.
The generic 'lying is bad' answer would have no place on either question. That lying is bad is obvious and the answers on the Trump questions provide insight into the national and international repercussion of the specific behaviour highlighted.
There is no national or international flavour that can be added to the Warren question. Anyone reading the Warren story will decide on their own which version of events they believe and there is no alternative analysis or deeper meaning to present about these events, which makes it a poor question.