You can use Kodi for IPTV (the IPTV Simple client even comes built-in). What we do not provide is any media sources, including those for IPTV.
Adding those is entirely down to you, and is entirely your responsibility. You can even use the illegal stuff if you wish, that is entirely your decision and responsibility - we do not tell you what you can and cannot do with Kodi. What we do reserve the right to do is to not support illegal usage, and to make things clear as to what exactly a user is doing and what repercussions may come of that.
Here the key points are that the user is doing whatever they are doing with a good and clear understanding of all of the above, and are not having decisions made for them by using 3rd party builds or add-ons which just install the
banned add-ons (wiki) without any explanation or indeed representation that they are "free and legal" which they are not (at least legal anyway).
Also we want people to understand what comes from us (Team Kodi) and what comes from 3rd party sources. We make the media player itself, but we do not promote or condone anything that uses such illegal pirated sources. Unfortunately what you say is all too true about it sometimes not being so clear, a point which is done deliberately by some of the YouTube hucksters and other sites around the net who want to make use of (and drag down) Kodi's good name to peddle their illegal wares.
If you have legal and legitimate sources on your Roku then you'll probably find similar ones available for Kodi. But if your used sources on the Roku are just as illegal as those you've seen by the 3rd party add-ons for Kodi, then you may want to have a wider think about things and perhaps look into something like a
PVR (wiki) subscription or similar more legitimate source like
Play On.
