Dear abc,
Absolutely not. The principle of our international society of nations is that every sovereign state has the right to security inside its own borders. Intimidation and threats by any foreign country are completely unacceptable, whatever the motive. The US itself stood up to the bullies of this planet during World War II, and then helped found the United Nations to make sure that no other bullies would surface. It would be a supreme irony if the US turned out to be the same as those it so nobly fought to defeat.
"Harbouring terrorists" is an especially poor reason for this sort of intimidation. No government can know for certain that all their citizens are not terrorists, and if some are, their existence by no means constitutes an endorsement of them by the government of that country. And even if the government did happen to secretly abet terrorists, this is still no reason for threatening to shower death and destruction upon the millions of innocent citizens of the country in question. This is the logic of psychopaths, and the methods of butchers.
Timothy McVeigh and his happy gang fit every definition of a terrorist, and as we all know they were also violently anti-Semitic... Does that then necessarily mean the US government was responsible for them, or deliberately protected them? What would have been the reaction in the US if the Israeli government threatened the Americans with bombing unless it "helped in the fight against anti-Semitism"?
Regards,