Please. 
Allow the use of lasers and handles on weapons at the same time. 
They are placed in different places on the weapons. 
Why are they in the same weapon modification?
Install a new weapon modifier for lasers only.

A trifle: Change the color of the laser from brown to black. 
The laser stands out strongly when painting weapons.

@ivan3000x

Weapons and particularly mods in the game are very abstract and not representative of real-life. You're opening a huge can of worms. Just as gear has arbitrary mod slots, so do weapons. Just accept it and try not too think to much about it.

But you're right, most combat equipped firearms will have a suitable optic for the expected range of engagement, an IR laser/illumintor for night vision use, a foregrip to help with recoil mitigation (largely based on your personal preference), a white light (flashlight), and a muzzle device (brake, flash hider and/or suppressor), and a sling. Precision rifles might also have a range finder and usually a bipod - and support weapons will also likely have a bipod.

In the game we have no night vision, so an IR illuminator like the APTIAL/PEQ modelled as a rail attachment in the game is really unnecessary and all the grips and muzzle devices have rather arbitrary buffs applied. It really is nonsense. There are other issues such as select fire ARs being arbitrarily single shot or full auto in the game. Then there are some optics which offer a first-person view and some that don't or are advertised as 8x magnification but are really only 1.1x. As I said above, best not to think about it unless they start taking this whole topic seriously and introduce a proper weapons smith and mod solution in the next title... but with the magic items we have in this game, that probably isn't in the cards.

That answer is always no, to the question not asked

Agreed it's not happening in TD2. Maybe in my fantasyland Ghost Recon, The Division 3 joint game in and around Mexico City - where "Hardcore Mode" will be "Immersive Mode" from Breakpoint, with a real gunsmith [using barrel lengths & ammo type to define bullet travel/drop/damage/sound..]

@virtual-chris
I agree with you. It's just a game.
I'm not talking about real weapons from life, weapon modifications and their reality in the game.

I'm talking about the attachment of the module to the weapon in the game.

handles and lasers are attached to different places on the barrel of weapons in the game, but they have one type of under-barrel modifications.
This annoyed me in the division 1.

Why not separate them?
The damage will increase slightly.
Everyone will only get better.

@ivan3000x I think you answered your own question, it's a bit of a matter of balance, it would let people stack too much certain stats perhaps in the devs view, it could be a multitide of reasons but i would guess that balance is most of it, few games do give the freedom to the point it's egregious such as tarkov, but when we have stats attached to them makes sense to limit the choice

@ivan3000x

I agree, but on one hand, you’re saying you don’t want/need realistic gun mods and on the other hand, it seems you want more realistic gun mods (I’ve got rail space, let me add another mod!)

Sadly, even Ghost Recon, Ubisoft’s more realistic tactical shooter game has equally limited gunsmith modding.

@virtual-chris @xcel30

I understand. 

It is a pity that the game does not allow us to do this.  
Although all the possibilities exist.

@latenitedelight Stay away from my Hardcore mode. You have Ghost Mode and Immersive, you can't have this too. (j/K)