Does a country escalate (retaliate) or de-escalate (not retaliate) when it is under attack?

This escalate/de-escalate issue has become a confounding problem nowadays.  Why?

Let's take a look at what some countries said.

Singapore had asked Asia not to escalate the tariff war because it will only hurt itself.  Thus, India should just eat the US tariffs without any retaliation.

The west had warned Iran not to retaliate when it was under attack by Israel.  Thus, Iran should just eat the Israelis missiles.

If we were to look at the above examples, it had become clear that a country shouldn't escalate or retaliate when it was under attack in a trade war or military war.

Recently, the US president had announced that he would impose a 50% tariff on the EU.  Thus, the EU should just eat the 50% tariff and not retaliate.  Moreover, the EU is in no position to retaliate because its private sector is contracting now.  Any retaliation will only boost the EU inflation and result in stagflation as the EU is having a super low economic growth now.