Well, it is not illegal, that is correct. Whether or not it is 'front running' is a matter of debate.
It certainly seems to me that they are running out in front of the order. I'm not sure how exactly you might be contorting the meaning of 'front running' for this not to apply.
Front running is trading in front of an unexecuted order, which you have because of your fiduciary responsibility to a client.
You're discussing trading in response to an executed order, which you have as a member of the general public.
If that's front running, then what isn't? Is my purchasing wheat futures in response to news of an predicted drought "front running" the orders that bakeries will be making?
'Front running' has specific legal definition (which has existed for a long time) which definitely doesn't apply to these cases. The contortion is in fact on your side.
What you are describing isn't front running (or even illegal).