[marten-de-vries]

They do not violate the relevant specification. They just implement it in a way that has not been done before with the user's convenience in mind.

That aside, your position is unrealistic: browsers regularly break non-spec conforming websites. They actually monitor such cases (telemetry) and try to work with popular websites to fix the issue before they ship the breaking update, but it's a tradeoff that is regularly made nonetheless.

[xg15]

While the actions were beneficial in this case, that argument would be more convincing if the spec itself weren't a constantly moving "Living standard" maintained by the exact same organisations that also develop the browsers. And even that spec is sometimes consciously broken in an "intervention".