when sharing a collection it asks invitee to sign in. or they can View only.

[aneal321]

I used to be able to easily share collections with people and they could like and comment.  now when they get the link it asks them to sign in or they can view only. 

[Charlie.D]

When you turn on sharing for an album, using the setting Anyone Can View will not require guests to sign in to see photos.   It is when Invite Only is set that guest login is required.

For more info see: https://helpx.adobe.com/lightroom-cc/using/save-share-photos.html

And for sharing your albums as part of a web gallery see: https://helpx.adobe.com/lightroom-cc/how-to/share-photos-on-web-gallery.html