Does the group you prefer to receive the Sacraments from have to necessarily be the group with whose positions you agree?  I don't think so, and believe they are separate questions.  And is the question generically about some group?  I write this because sometimes you find a priest whom you consider holy, pious, a good confessors, etc. ... with whom you may not necessarily agree on all their positions.  That has in fact been my case.  I haven't always been too fond of many of the clergy who happen to align with my own doctrinal positions and, for the purposes of receiving the Sacraments, think of specific priests rather than as "groups", since one does not receive the Sacraments from a group, but from a specific individual priest.

I will receive sacraments wherever they are not doubful.

However, as I profess the rigourist interpretation of Extra Ecclesiam Nulla Salus, priests of the SSPV would never knowlingly administer sacraments to me.

Further, because I, although sedeprivationist in my ecclesiology, have no scruple in attending una cuм Masses and do in fact attend such Masses, some sede clergy would refuse me communion or unction if they knew this.

We shouldn't think of each other as "enemies" and I don't know why people won't work on doing that?  Am I missing something? 

Agree. The devil knows that by "working" on the clergy, he can profit more than attacking individual lay people.

I agree.  But I wrote this letter 

https://www.cathinfo.com/anonymous-posts-allowed/the-tears-of-a-traditional-catholic-mother/

and was told not to bother the clergy.

I think we all have to do our part.  We have enough books and examples of Saints, to ready ourselves for Spiritual Warfare.  If you are with God, who can be against you.  Make sure you are praying your Rosary, offering all your trials of your day, and getting to the True Sacraments as often as possible.  We should help each other in the process, not bring each other down.