Is specifying link colours a violation against WCAG’s Success Criterion 1.4.8?

The text of the WCAG's Success Criterion 1.4.8 page says:

Success Criterion 1.4.8 Visual Presentation (Level AAA): For the visual presentation of blocks of text, a mechanism is available to achieve the following:

Foreground and background colors can be selected by the user.

One may choose from five different given techniques to satisfy this part of the criterion: C23, C25, G156, G148, or G175. The latter, G175, states that a colour-picking tool must be provided.

All the others techniques except for G156, however, explicitly mention that no background and no foreground colour must be specified for the texts, at least not for the main content's texts.

However, is specifying colours for the links in those texts (supposing no colour-picking tool is provided on the page) a violation against Success Criterion 1.4.8, or is it satisfactory due to the fact most modern browsers are compatible with the demands of the technique G156, since they let the users change the page's colours?

If so, then is it acceptable to specify background and foreground colours also for the main content's text, given browsers let the users change these specifications?