> Lack of contrast hinders everyone with any kind of vision issues (old/colorblind etc.)
False. Someone with some kind, but not everyone with any kind. This broad stroke that you've just painted is counter to the goals of accessibility.
> “Too much” contrast means young hipsters complain it burns their eyes.
Let's not trivialize disabilities we don't even know exist. But if you wanted to research this, you can look up the term "photophobia" or "light sensitivity".
> Even the highest standards for readability leave a comfortable range for expressing creativity (and soft colors), it’s not like they require #000 on #FFF.
Again, false.
Let's consult Accessibility Requirements for People with Low Vision:
> 2.4.2 Light and Glare Sensitivity
> Many people with low vision have extreme sensitivity to light (called photophobia). Bright light makes it difficult or impossible to see, and causes eye pain and headaches. For some people, the normal brightness of a computer screen with a light background is not readable and painful. They need to change the background to a darker color. Glare sensitivity is common with age-related vision changes and cataracts.
> [...]
> 3.1.2 Text Contrast
> As mentioned in the Light Sensitivity section, some people need low brightness, especially for backgrounds. Some people who need low brightness for backgrounds also need low brightness overall and thus need low brightness text.
> Other people need high contrast between text and background, including many older people who lose contrast sensitivity from ageing. Some read better with dark text on light background.
> For some people, common color combinations or colors from a limited color palette work fine, for example, black text on white background or the inverse with white text on black background. Other people need to select more specific background and text colors. For example, people who need low brightness overall, need to select the specific background and text colors that provide sufficient contrast for them yet not too high brightness. Readable and optimal color combinations differs vastly among individuals and can even vary for one individual depending on conditions such as fatigue and lighting.
(emphasis mine)
Source: https://w3c.github.io/low-vision-a11y-tf/requirements.html