Send email on comment to users depending on Taxonomy term selection in node
You should Load the Entity (node) from the comment's data.

Then pass that node to a component rule, which actually checks the taxonomy of the node and sends the appropriate email.

Here's a step by step.

First create a component:
1) Go to Rules -> Components -> Add new component
2) Select Rule
3) Name and Tag the component
4) In variables select 'Entity Node' and give it a label and a machine name. Example 'comment_node'
5) Add your conditions. Probably good idea to check node type and of course the taxonomy term you were looking for.
6) Add an Action. Here you should send an email.

Now go to your rule:
1) In actions add 'Fetch entity by Id'. Select 'node'. Use data selector and put 'comment:node:nid' in the id.
2) Then add a Loop
3) In the loop add an action. That action should be your component you created previously.
4) Pass the fetched entity into the component and you should be done