I don't believe Snape values his love for Lily, past or present. I believe Snape is scheming to his own ends and by his own mercilessly practical means. He's not the best at it, but he's left the chump train.

Snape forced the escalation in order to get justification to do exactly what he did at the end of the first scene of chapter 75, where the following describes him admonishing the top Slytherin bullies:

"You will do nothing," hissed their Head of House. Severus Snape's face was enraged, when he spoke small spots of spittle flew from his mouth, further dotting his already-dirtied robes. "You fools have done enough! You have embarrassed my House - lost to first-years - now you speak of embroiling noble Lords of the Wizengamot in your pathetic childish squabbles? I shall deal with this matter. You will not embarrass this House again, you will not risk embarrassing this House again! You are done with fighting witches, and if I hear otherwise -"

Snape has cut the head off the Slytherin Bullying Machine, intending to see the machine fall apart without it. The non-Slytherin bullies were probably never that organized (fucking Gryffindors), and I suppose are meant to sympathize with the little girls and de-value bullying behaviors over time. It may be intended that they will stop 'naturally,' once there are fewer Slytherin bullies to respond to.

In fact, Snape isn't just behind the escalation, he started it all. Chapter 68 ends with Hermione thinking about who she could get as a mysterious wizard, though not in those terms, when she sees a flash of light. She thinks that light, and a little later a sound, is from Fawks follows it to her first bullies to beat at the beginning of chapter 69.

Just before Hermione hear Just Mike cry for help, we are given the following hint, alone as its own paragraph:

She never saw the phoenix.

She never saw the phoenix because there was no phoenix, only Snape.

Further, Snape was personally managing the escalation. In chapter 74, Dumbledore says the following about the battle of The Bully Jaime Astorga vs. Sugar And Spice And Everything Badass:

There is not enough magic in eight first-year witches all together to defeat such a foe. But you could not accept that, Harry, could not let Miss Granger learn her own lessons; and so you sent the Defense Professor to watch over them invisibly, and pierce Astorga's shields when Daphne Greengrass struck at him -"

The text never counters this claim. We are never presented with evidence that eight determined first-years could defeat a single Jaime Astorga other than the narrative of the events themselves. And in the same chapter as that narrative, 72, we learn that the Mr. Astorga is "a promising upstart on the youth dueling circuit" and that he does not understand how his shield was pierced. Again, we are given no reason to doubt his claim that his shield should not have been pierced, except that it happens it was.

Is it more likely that Dumbledore and Mr. Astorga are wrong about the unlikeliness of that event, or that the event did not occur as it was described from Hannah Abbot's perspective. Dumbledore has a long history of making heroes out of children, and Mr. Astorga was a competitive duelist. I suggest it is more likely that they were right, and Snape assisted S.P.H.E.W. in a wonderfully Slytherin fashion.

I don't see any obvious points where Snape helped out in the battle where Hufflepuff loyalty resulted in Tonks Time and the Snowballing Lie in chapter 73. Maybe he didn't always have to step in. And maybe he made the last bully standing (or falling down) drop his wand back in chapter 69. But even when he doesn't ditry his hands he is playing both sides, guiding the bullies and S.P.H.E.W. toward each other and ensuring that S.P.H.E.W. wins.

I'd like to know what Snape had planned for the last battle, before he was interrupted. I would guess that was the last battle he intended to happen. I don't know what he could have wanted to see next.

Anyway, after that Snape had the ammo he needed to pull the rug out from under the Syltherin bullies. And if he hurt Hermione at the end, and if he risked the emotional or even physical health of eight little girls, and if he humiliated his allies on the darker side of wizardry by shaming their children, why should he care? Snape is so Syltherin the hat spoke the instant it was on his head. His plans are cunning. His devotion to his ambition is complete.

Snape is Hermione's mysterious old wizard. (He makes up for only being thirty-whatever by being extra mysterious.) He does not need to act with her interests in order to play this role. Dumbledore attempted to send HJPEV to live with abusive step-parents and even says the following back in chapter 68:

I am not Harry's friend, alas, but only his mysterious old wizard."