20 years as an electrical engineer is where my knowledge & experience comes from.
I’ve seen things melt, explode, short circuit, overload & people get electrocuted.
Prolonged overheating due to an internal fault will lead to temperatures not designed to be absorbed by the plastic ABS shell as well as other internal components. We don’t have sufficient info from the OP to determine whether it’s normal operation or faulty operation. Yes, the PSU gets hot during heavy use so to just say “it’s ok, mine gets hot too” is a ridiculous comment and unsafe as you just don’t know. Removing the outer plastic shell which acts as an insulator to minimise the risk of contact with metallic parts is definitely a shock hazard as you are removing the very component used to prevent direct contact with metallic components which can become “live” under certain fault conditions.
The psu contains, among other things, a step down transformer which converts your incoming supply voltage (110V/230V) down to sub-20V and a DC rectifier to change AC to DC to power your laptop. Under normal operation, yes the components get hot, but in abnormal conditions they can overheat and reach temps they are not designed to cope with and lead to melting of internal parts as well as the outer shell. IYKYK