yes, if it is on SFPRP - single family private residential property - then you should do a report. you can either report in game, or through one of the forms at the top here.
i have mixed results asking help chat at https://wayfarer.nianticlabs.com/new/help to remove these, but some people use that. they usually tell me to use one of the forms.
It can sometimes be unclear if the property should be considered SFPRP: Private Residences, Farmland & K-12
**Easements, “right-of-ways,” and sidewalks are too broad to make a global statement on, but the guidance is the same as above - if it is part of a private residence, it is ineligible.
Sometimes they choose to leave ones that I think should be removed if the evidence is not clear.
More straightforward wording is in the clarification specfic to LFL’s Little Free Libraries
If a LFL is placed on eligible property in such a way that any visitors may obstruct the entrance, may encourage trespassing, or may present danger from nearby traffic, they should be considered ineligible.