This is not true. "Ich heiße Hans" is usually translated as "My name is Hans" in English. Though "I am called Hans" is a possible alternative, the former can be found much more frequently, maybe because the latter could as well be interpreted as "they call me Hans, but in fact my name is Klaus", and this is not the meaning of the German verb "heißen" which defines the real name.
Sure, but there is always a but: Think of a trans*-woman. She may tell you "Ich heiße Klara" (My name is Klara) but her legal name is Peter.
Reminder: In Germany you cannot change your first name easily. Its an expensive, time taking process that requires two psychatric reports and a permission of a family court.
Translating names actually used to be common. This is why we have historical characters like John the Baptist and Christopher Columbus, the Hebrew preacher and Italian explorer respectively. We stopped doing it a while ago, though, not sure why, but it's a practice at least dating back to Ancient Rome with Commius the Gaul and Arminius the German.
"The bears are named Hans und Karl" I think should be accepted. Since it is an introductory sentence, and always you can translate this with the verb "Heißen" "My name is Jane" = "Ich heiße Jane", "I am Jane" = "Ich heiße Jane", "I am called Jane" = "Ich heiße Jane," "I am named Jane" = "Ich heiße Jane"
"heißen" is a verb, meaning "to be called".
And all verbs are conjugated, e.g.
ich heiße - I am called
du heißt - you are called (one person informal)
er/sie/es heißt - he/she/it is called
wir heißen - we are called
ihr heißt - you are called (several persons informal)
sie heißen - they are called
Sie heißen - you are called (formal one or several persons)
If we direct translate Spanish to English we sound like Yoda. We are taught not to direct translate word for word but to what the closest meaning represents in the other language. No one in the US, or probably any other English speaking nation, says "this is called" in reference to ones personal name. It sounds rude, like you're relating them to an inanimate object. The bears are Hairy and Kurly, their names are Hairy and Kurly, the bears' names are Hairy and Kurly. So why are none of these correct?
Edited for clarification and to fix punctuation.
The sentence I wrote, but was erroneously marked wrong, was "the bears are Hans and Karl". I was making a point that it doesn't matter what the names are. You don't directly translate a language, but pick what is the closest to which is trying to be conveyed. In English "I am called" usually has a bad conetation. Example sentence: I was called fat by my mom growing up. These bears are Hans and Karl, they're not called Hans and Karl like someone being called a bad name. Just because the direct translation is "the bears are called..." does not mean that is the appropriate translation.
"The bears call Hans and Karl" would be either "Die Bären rufen Hans und Karl" (if they are just shouting in order to call Hans and Karl to come) or "Die Bären rufen Hans und Karl an" if they use a telephone for getting into contact with them (highly improbable for bears, though).
It doesn't matter what the bears are called, they never come when you call them. What a stupid bloody exercise (unless you're a zookeeper or Sir David Attenborough).