I believe there is some confusion between Paramyxoviridae and Paramyxovirinae. RSV is in the family Paramyxoviridae, but it is not in the subfamily Paramyxovirinae. Paramyxoviridae fam is the high-yield association as opposed to the Pneumovirinae subfamily. (See amboss link, where the mnemonic is for the family, not the subfamily. See also First Aid.)
https://www.amboss.com/us/knowledge/General_virology#Z30cf1c844b0e42bed39f00950cf3a137
More:
The family Paramyxoviridae contains two subfamilies that are relevant to humans: Pneumovirinae and Paramyxovirinae. The subfamily Pneumovirinae gives rise to the genus Pneumovirus (respiratory syncytial virus). The subfamily Paramyxovirinae gives rise to the genus Morbillivirus (measles virus/ rubeola), to the genus Respirovirus (para-influenza viruses 1 and 3), and to the genus Rubulavirus (mumps virus and para-influenza viruses 2 and 4).[3] The transmission occurs via respiratory droplets or direct contact. [3]
https://www.ncbi.nlm.nih.gov/books/NBK567794/
Maintainer Slack decided to keep it as Pneumoviridae in this case, going to merge my edit explaining the difference in resources for clarity