Explain them it's simply STUPID, if the host is down you are only hogging the nagios machine with useless checks (which i expect they can see will have no effect whatsoever). Decrease the hosts check alive interval if you want (it does a check_ping so are already doing a service check if taht can be used as an excuse) as i said i doubt it can be done without modifying the source of the scheduler.
back to the plugins:
It looks like nagios can't get a valid result from those plugins so there really is no CRITICAL state to be counted.
Try running the plugins from command line as user nagios and see if you can get a result. It's probably some misconfiguration or firewall problem (for the second type of error), i.e. you can't make a check_ssh if you don't have ssh access through some firewall.