Why are Lands colorless?

Hi guys,
I was a bit puzzled when I wanted to build a green deck and searched for forests. I thought I had to rightclick on green in deck editor, then rightclick on lands... only 1 card appeared?! Then I realized, lands are colorless. Why is this? I had to text search for "Forest" in type field, which worked.
Is this intended?
TIA
I was a bit puzzled when I wanted to build a green deck and searched for forests. I thought I had to rightclick on green in deck editor, then rightclick on lands... only 1 card appeared?! Then I realized, lands are colorless. Why is this? I had to text search for "Forest" in type field, which worked.
Is this intended?
TIA