I've been looking at LG smart TVs to eventually cut the cord...cable TV.
You can try removing any app you may have recently added including web browser. Especially if you
got the app from other than developer or from sources other than say Google store. Even some of those
will install adware, spyware and malware. You really can't be too cautious.
You can reset your TV to default settings. That means you would need to reinstall any apps such as
Google TV or Sling TV that you may have installed.
If you still are seeing those porn ads after resetting the TV to default it could be the router is the problem which
would require resetting it to default settings and resecuring it.
Reset an LG Smart TV to Factory Settings
“Every atom in your body came from a star that exploded and the atoms in your left hand probably came from a different star than your right hand. It really is the most poetic thing I know about physics...you are all stardust.”― Lawrence M. Krauss
A 1792 U.S. penny, designed in part by Thomas Jefferson and George Washington, reads “Liberty Parent of Science & Industry.”