The value of reading time should be measured against Medium’s expectation of reading time (as it is displayed in minutes, rather than number of words). Medium did originally take into account read time in the member payment calculations. So if a reader clicked on a 1 minute read, between 20–60 seconds, it would count as being “read” and therefore as “engaging the reader” and be paid at a higher rate than the 1 minute read that the reader zipped down to clap symbol, clapped 50 times and left in 15 seconds.
This is to prevent the devious and money-oriented to hiring friends presumably, who will clap without reading to provide pennies to the authors. The limit to the number of stories that can be clapped for in a 24 hour period attempts to address the same rorting.
Fear not for your poems, short, medium or long. So long as a reader is genuinely reading (and by the way, I usually spend 8–10 minutes on your poems, Jef, reading and re-reading aloud to satiate my enjoyment of your mastery of language), they’ll be paid the full amount possible (which is also dependant on other factors such as how much they read, if they’re paid members, if they comment, or share on other social media and etc).
Medium isn’t — at least not with this ploy — trying to rid the site of poetry. They’re just reapplying a part of the algorithm that is essential to deter somewhat those who believe that all internet sites are fair game for cheating.