Don't name it bind.cfg.

I'm probably wrong but tf2 might be confusing the "bind" in "exec bind" as a keyword so it will give an error. Try naming it like binds.cfg or something like that

You have unbindall in your config, which will unbind your text binds, and your exec nullmove script is doing nothing because you put it before unbindall, so you might want to move it after unbindall

r_drawviewmodel 1;viewmodel_fov 110
unbindall
cl_autoreload "1"
exec nullmove
exec bind
bind "0" "slot10"
bind "1" "slot1"
bind "2" "slot2"
bind "3" "slot3"
bind "4" "slot4"
bind "5" "slot5"
bind "6" "slot6"
bind "7" "slot7"
bind "8" "slot8"
bind "9" "slot9"
bind "b" "lastdisguise"
bind "c" "voice_menu_3"
bind "e" "voicemenu 0 0"
bind "v" "+voicerecord"
bind "i" "impulse 201"
bind "g" "+taunt"
bind "h" "+use_action_slot_item"
bind "j" "cl_trigger_first_notification"
bind "k" "cl_decline_first_notification"
bind "l" "dropitem"
bind "m" "open_charinfo_direct"
bind "n" "open_charinfo_backpack"
bind "o" "explode"
bind "r" "+reload"
bind "u" "say_team"
bind "z" "voice_menu_1"
bind "x" "voice_menu_2"
bind "y" "say"
bind "c" "voice_menu_3"
bind "'" "r_drawviewmodel 0 1"
bind "`" "toggleconsole"
bind "," "changeclass"
bind "." "changeteam"
bind "/" "+movedown"
bind "-" "disguiseteam"
bind "SPACE" "+jump"
bind "TAB" "+showscores"
bind "ESCAPE" "cancelselect"
bind "INS" "+klook"
bind "PGUP" "+lookup"
bind "PGDN" "+lookdown"
bind "PAUSE" "pause"
bind "SHIFT" "+duck"
bind "F1" ""
bind "F2" "show_quest_log"
bind "F3" ""
bind "F4" "player_ready_toggle"
bind "F5" ""
bind "F12" "screenshot"
bind "F7" "save_replay"
bind "F8" ""
bind "F9" "askconnect_accept"
bind "F10" "say .ss"
bind "MOUSE1" "+attack"
bind "MOUSE2" "+attack2"
bind "MWHEELUP" "slot1; r_drawviewmodel 1;viewmodel_fov 110"
bind "MWHEELDOWN" "slot3; r_drawviewmodel 1;viewmodel_fov 110"
bind "q" ""
bind t "slot1;slot3;r_drawviewmodel 1;viewmodel_fov 110"
viewmodel_fov "110"
fov_desired 90

alias "+ambyzoom" "fov_desired 70; viewmodel_fov 110;"
alias "-ambyzoom" "fov_desired 90; viewmodel_fov 110;"
bind "f" "+ambyzoom"

alias "undisguise" "disguise 8 -2"
alias "+sapper" "slot2;+attack;r_drawviewmodel 1;viewmodel_fov 110;"
alias "-sapper" "lastinv;-attack;r_drawviewmodel 1;viewmodel_fov 110;"
alias "medon" "slot2; disguise 5 -1;"

bind "q" "undisguise"
bind "mouse5" "+sapper"
bind "5" "medon"
bind "[" snd_restart
cl_crosshair_file crosshair2
cl_crosshair_scale 20

Also like setsul said above, make sure in windows explorer you enable "show file extensions", some types of files will hide the .xxx part, so naming your configs something.cfg it will become something.cfg.cfg

Why do you have like your entire autoexec in your spy.cfg?
The point of class configs is to only have those commands that you want to change for that class specifically.
I mean it's not really breaking anything, it's just a lot more convenient and less confusing to only keep the essential stuff in you class configs and keep everything that's the same for all classes in your autoexec and you probably fucked up your binds because there's such chaos in your configs and now it's that much harder for you to find the error.
I think the best way to do it is to make like a standard.cfg file and put exec standard in all your class configs.
Now if you have a bunch of commands that are different for one class, but the same for the 8 other classes, you don't have to copy them into all of your class configs, but only in your standard config and keep the class configs clean.

If you do that and keep all the stuff you don't want to change from class to class in your autoexec, your binds should work fine.
Just put the binds in your autoexec. No need to have a extra cfg for it.
But if you really want to keep an extra config for the binds, just put "exec binds" in your autoexec.
Like I said, stuff that you don't want to change on different classes doesn't belong in your class configs.

Hmm on my screen unbindall is on the very top and before all binds, so it should't change anything.
Still pointless to have it, since the binds in your autoexec/class config will override all previous binds anyways.

Thank you all so much. I finally fixed it.
Appreciate all the feedback.

Configs are execed in order, so if you put unbindall after something then it would unbind, the purpose of putting unbindall in a config is to get rid of all unnecessary binds.

What did you do to fix it?