It is dangerous to tenants' lives that the CO2 and other kinds of gas become accumulated inside.
No. It is normal for CO2 levels to be higher in inhabited spaces.
However, there are levels of CO2 that are dangerous. Usually because of other factors such as improperly installed heating systems or inadequately vented kitchens etc. This should not normally be a problem. If in doubt, measure it.
The levels of CO2 in the air and potential health problems are:
250 - 350 ppm – background (normal) outdoor air level
350- 1,000 ppm - typical level found in occupied spaces with good air exchange.
1,000 – 2,000 ppm - level associated with complaints of drowsiness and poor air.
2,000 – 5,000 ppm – level associated with headaches, sleepiness, and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.
>5,000 ppm – this indicates unusual air conditions where high levels of other gases could also be present. Toxicity or oxygen deprivation could occur. This is the permissible exposure limit for daily workplace exposures.
>40,000 ppm - this level is immediately harmful due to oxygen deprivation.
Wisconsin dept of health
So are the above policies of apartment managers reasonable?
In my view, yes.
You shouldn't pay your apartment owners to heat the outside air. You should pay them to heat the interior of your apartment.
There is also the consideration of harm to the environment, but I know that's not a concern in some cultures.
If you measure over 1000 ppm CO2, and are certain it's due to factors beyond your control (e.g. not due to burning candles etc) you have good cause to ask the building owner to do something about it.
The Wisconsin "normal" levels are actually low and may be out of date. Outside CO2 levels rise in winter (and probably near roads etc) and are probably rising year on year.
US DOE CDIAC
So don't be alarmed if your outside CO2 levels are substantially higher than "250-350 ppm". That's a global problem, not a problem with your particular home.