I don't think this is the case at all. I spoke to some NYMR people recently and asked about this. Their view was that it would be great for them and the area but it would cost a lot and they have just finished re installation the roof at Pickering and need to fund bridge repairs.
The section through Pickering town would be an issue although it is not imposable and if we are talking of mainline services running to Whitby then a diversion and a Pickering Parkway station to the east might be possible.
It should be remembered that when the NYMR was just coming about Pickering council wanted it to be relocated to terminate on the outskirts of the town with the existing station being demolished and turned into a car park and housing.
Don't know who you've been speaking to, but evidently there has been a counter piece in one of the local papers by the Moors GM, explaining how damaging such a reopening would be.
In short, this one comes round every few years, with someone making some hot air about reopening. The NYMR hasn't got the money to do it, and would only add a significant maintenance liability if they did. Plus, the likely ticket price would probably be prohibitive, and the journey time too long for a family day out. (Remember the NYMR's primary market is tourist, NOT enthusiasts).
The 18 miles of the NYMR is largely at capacity; the Esk Valley line into Whitby certainly is. Where would the extra trains go?
Where would you find the mythical steam locos to work these extra services? There is something of a national shortage right now! Where would yopu find the people to operate them with?
The only way it could happen, is via a publicly funded reopening of the whole route to NR standards. Even then, it would still be a tortuous route, as it never has been much more than the present day permitted speeds. That would mean the mainline services getting priority, which would effectively mean the end of the NYMR. Be careful what you wish for!
This is without considering capacity issues at York, which is chocker as it is!
A lot of hot air by politicians, who don't have a full grasp of the issues.