Pixelmator always felt like it was built by Apple even before they touched it. That absorption felt more like a formality than an acquisition and the product has pretty much stayed exactly the same since.
Colo.io is different, mostly because it's a web app which is already a strike given Apple's allergy to anything on the open web. Also it was made by one person so would be a low-cost acquihire that neutralizes a potential competitor outside of their walled garden. Founder walks with a few mil plus a senior role and the web loses another good tool. Net win for Apple, arguably for the founder and a net loss for the web ecosystem. Business as usual.
I don't think this is the full story. 99% sure there's either a brand acquisition or tech licensing of some sort involved that he's not allowed to talk about...