Earlier quoted context omitted.
"Link tax" is clearly chosen in bad faith, like in other cases where that wording had been used. What's really happening is that Google Search shows previews of large parts of articles such that visitors don't go to origin sites to generate page impressions/ad playouts. Which is especially problematic since Google/Alphabet is either an ad provider on the skipped news site or its competitor.
How many characters of preview would be reasonable? 50? 100?
A better criteria is: what fraction of people does it stop from visiting the source (because they got the information they were looking for from the summary). Yes, yes that system has it's own problems, but it is more holistic that string.length().