Pull starting can both be good or bad. It becomes bad when the tires slide in high gears. You can very well end up with at he least bent pushrods and if the tires can get a good grip bend a rod.
When you know that something could be in the cylinders never try to pull without pulling with all spark plugs removed to make sure all oil or water has been blown out thru the spark plug holes that could fill the firing chamber to block rotation and bend a rod.
When the tires slide you need to first pull the valve cover to check for stuck valves. One stuck valve can slide a tire. Then if the tire gets a good grip on something the push rod goes into a U.