They both go against core gurmat teten of equanimity - "Harak sog te rahe nearo" and " jo nar dukh main dukh nahi maane | kanchan maati maane ||"
Dancing / excessive rejoicing is also a reflection of kachi avastha = "nachan kudan man ka chao | nanank jin man bhou tina man bhao ||"
Wailing / crying is not gursikh like as is evident from "Jini pachata Hukam tin kade na rovna"
We shuold strive to behave with such calm at both occassions that outsiders are forced to ask - "is this a funeral or a wedding ?"
What does the sangat think ?