People might not like the spec or it might be incomplete, but adhering to it is a very important part of improving it until it's a good one.
Now I'm no webdev, but I could very well imagine that the spec is already a good one. So the situation might be even worse.
Not arguing in favor of this particular choice, but yes. That is exactly what "should" means in most cases.
For instance, in RFC 2119: https://tools.ietf.org/html/rfc2119
> SHOULD This word, or the adjective "RECOMMENDED", mean that there may exist valid reasons in particular circumstances to ignore a particular item, but the full implications must be understood and carefully weighed before choosing a different course.