it is a bit more tricky than that. It is perfectly fine for foreign leaders to meet with potential election winning parties and discuss policy options. That is normal and done by everyone important enough to be heard.
Also journalists are not too stupid to see who likes who even if it isnt said out loud
Now if he comes out in public to endorse them in the next elections that would be meddling and justify such a response. But shitheads meeting to make shithead plans doesn’t cut it yet because normal people also meet normal people to make plans in that context.