Disclaimer: Please do not take the following as condoning Mihai Tudose (Romania PM)'s words.
From the links provided in the edit, it is very clear that the title of the question is a notable misrepresentation of the issue.
The words are (emphasis mine):
"I have sent message that if the Szekler flag flies over the institutions over there, they will all fly next to the flag. Autonomy for Szeklers is out of the question.
As long as they sing in their yard, that is one thing, but from a legal point of view things are very clear,” Tudose said in a video of the interview.
The (local/regional) institutions are part of the Romanian state and there will be laws about what flags may be flown, and how. Adding a different flag means a challenge to the authority of the state1, i.e. it is a crime (even if it certainly is not punishable by death)2.
Second, it is noted from the news pieces that Tudose's comments have been criticized and/or softened by member of his own government, and that there seems to be no attempt at enacting a law in line with the declarations. And that the PM seems to lack any support for such a change (up to the point that his government depends of the support of an Hungarian minority party). That makes the issue just a big mouthed idiot using big words3 to embarrass himself and his country just to get the populist vote4.
Compare that with Orban and Kaczynski tight control of their respective governments (including their parliaments and increasing control over the judiciary), and the fact that those have actually taken actions (laws, etc.) towards their ends.
Also, the "death threat against national minority" interpretation is an interested one, coming from Orban's government. One of Orban's stated goals is challenging the Triannon treaty (end of WWI), and reincorporating the parts of Romania with Hungarian population. To that end, claiming that the Hungarian population in Romania is in risk is a very useful narrative to convince his voters of the need of such actions (and, in consequence, of their support to his government no matter what).
In short, while Mr. Tudose could certainly remember his position5 before saying certain things, the interpretation of his words as a threat of ethnic cleansing is way too far-fetched (ok, let's be clear, it is just a lie). But of course, nationalist tensions are useful to distract the public from other issues (like for example the corruption issues surrounding Romania these days).
Note how the second paragraph allows for freedom of speech/political action, thus voiding one of the issues from my comment.
2I do not know the specific Romanian laws, but the EU forbids the death penalty.
3Word of the day: Hyperbole.
4Must be the sign of the times...
5And the ever present risks of some idiot understanding his words as a go-ahead for criminal activities.