Laskern – cherry picking sources doesnt make those who dont follow them mekilim (despite the late unlamented RGP). No less an authority than the Shlah saysthat it is a SAKANA to say Mizmor Shir Leyom Hashabbos after shkiah. How many shuls do you know that are makpid to ALWAYS finish kabbolas Shabbos earlier than shkiah?
(And if you know some that are, they are almost certainly being meikil in other areas such as saying Shema before the zman….)