Drop read throttling for wiki sites. Read thottling was introduced with Pywikibot 1.0 to throttle read access to wikis because screen scraping was used to retrieve data. Now we have API access and read throttling is not needed any longer. The minthrottle is set o 0 and I have no information that someone uses that variable with other values.

Read throttling is usefull for foreign web pages identified by its url but not by the site. See T152350 where connections to the same host are throttled.