It seems like it comes down to what constitutes a public forum and it seems odd to me that privately owned spaces can be public forums even if they want to be c

It seems like it comes down to what constitutes a public forum and it seems odd to me that privately owned spaces can be public forums even if they want to be considered that way. If the costs of running and maintaining a space fall up a private entity I don't understand how they can be compelled to host something they don't want.