Because you can't count soup. It's the same thing with rice "spiser ris" not "spiser et ris" or juice "drikker sok". You could use "et" if you want to talk about a very specific soup, though, as in "He is eating a soup with onions in it". And you could also make it countable by adding a countable noun, as in "a plate of soup".
There are two noun types for "jordbær". "Et jordbær" which is the berry that we pick and eat. And "en jordbær" is a botanical term for the strawberry plant, it is very rarely heard outside very specific situations. Google is not exactly wrong, but they didn't pick the most used translation when algorithm decided on this.