Yes, new users of any intoxicant can feel uncomfortable, act stupid or even panic. It is simply not their “drug of choice”. It’s all personal perspective and I don’t consider these to be side effects.
The stigma, propoganda and illegality around pot also increases the risk of panic and fast heart rate.
Pot doesn’t make the heart “race” (except the few individuals who panic). In some users it increases the rate about equally to walking (which can cause a heart attack in the sick). The components of the smoke are not good but far less smoke is inhaled by typical pot use than with tobacco use.
Also, pot does not have to be smoked and it gets easier to do so when it is legal/cheap. In Colorado and California many people are quitting smoking completely and switching to vapor and edibles.
Basically, smokeless pot is about as dangerous as a brisk walk to people with poor heart health. Far safer than any comparable drug out there
There is what “you consider” and then there is physiology.
Physiology wins