If you enter bgcolor="chucknorris" in any of the HTML elements supporting the bgcolor attribute, you'll actually get an appropriate blood red shade of color.

How come this is a thing? were the designers of the standard fan of the actor?

The real reason is rather linked to historical implementations of these attributes in Netscape Navigator, which interpreted the chain of characters as if it were hexadecimal numbers and interpreting any unknown symbol as a zero. Then they'll be split in 3 groups out of which the first 2 characters will be used for the hexadecimal color value.

See the interactive representation below. You may type down a different name to see what would be the result!

c00c0000000

# c00c 0000 000

#c00000

Note that the breakdown will not match in all cases. For example, if you type a known color name, like "magenta", then it'll actually come out as magenta, of course.